Diel Activity Patterns Research Articles

Evolution of Large Eyes in Stromboidea (Gastropoda): Impact of Photic Environment and Life History Traits.

Eyes within the marine gastropod superfamily Stromboidea range widely in size, from 0.2 to 2.3mm - the largest eyes known in any gastropod. Despite this interesting variation, the underlying evolutionary pressures remain unknown. Here, we use the wealth of material available in museum collections to explore the evolution of stromboid eye size and structure. Our results suggest that depth is a key light-limiting factor in stromboid eye evolution; here, increasing water depth is correlated with increasing aperture width relative to lens diameter, and therefore an increasing investment in sensitivity in dim light environments. In the major clade containing all large-eyed stromboid families, species observed active during the day and the night had wider eye apertures relative to lens sizes than species observed active during the day only, thereby prioritising sensitivity over resolution. Species with no consistent diel activity pattern also had smaller body sizes than exclusively day-active species, which may suggest that smaller animals are more vulnerable to shell-crushing predators, and avoid the higher predation pressure experienced by animals active during the day. Within the same major clade, ancestral state reconstruction suggests that absolute eye size increased above 1mm twice. The unresolved position of Varicospira, however, weakens this hypothesis and further work with additional markers is needed to confirm this result.

Circadian fruit phenology: An overlooked crucial aspect of plant‐frugivore interactions

Abstract The intrinsic ability of plants to face environmental diel changes is paramount for flowering and interactions with pollinators and herbivores. Surprisingly, despite the commendable research efforts on the ecology and evolution of fruit‐frugivore interactions, very little is known about how fruit ripening and dropping vary throughout 24‐h cycle. Even less is known about the potential consequences of circadian fruit phenology on plant interactions with mutualistic and antagonistic frugivores. We illustrate for the first time how the circadian pattern of fleshy fruit dropping and its matching/mismatching with the diel activity of functionally diverse frugivores (fruit/seed predators, seed dispersers, pulp feeders) can drive the outcome of complex multispecies plant‐frugivore interactions. To that end, we used camera trapping to quantify the circadian fruit dropping of a mammal‐dispersed tree, Pyrus bourgaeana, and the diel activity patterns of its functionally diverse vertebrate frugivores during two fruiting seasons in two tree populations of Mediterranean Spain. Using a large data set (20,878 frugivore visits and 701 fruit‐dropping records), we evaluate the adaptive hypothesis that the circadian pattern of fruit dropping will match the diel activity of seed dispersers rather than that of fruit/seed predators. Fruit dropping during daytime doubled that at night‐time, being considerably consistent across and within seasons, study sites and individual trees. Specifically, overlaps between circadian patterns of fruit dropping across and within seasons (0.83 and 0.84 ± 0.02, respectively), study sites (0.95) and individual trees (0.68 ± 0.01) were always high. Whereas seed dispersers (mammalian carnivores) were mostly nocturnal, the most frequent fruit/seed predators (cervids) were mostly diurnal. Consequently, and contrary to our expectations, circadian fruit dropping was more aligned with the diel activity of overabundant fruit/seed predators than with that of carnivore seed dispersers. Our study illustrates how quantifying the circadian patterns of fruit dropping, the diel activity of functionally diverse frugivores, and the matching/mismatching between both patterns can contribute to a better understanding of multispecies plant‐frugivore interactions. Circadian fruiting phenology is an overlooked key attribute for most tropical and temperate fruiting plants, which patterns, mechanisms and outcomes must be fully investigated. Read the free Plain Language Summary for this article on the Journal blog.

Ecological Adjustments and Behavioural Patterns of the European Badger in North-Western Italy

The European badger is a highly adaptable species, inhabiting a range of environments across Europe, from woodlands to urban areas, with its behaviour influenced by environmental conditions and human activities. This study examines the badger feeding habits, patterns of diel activity, and sett site choice in north-western Italy, assessing how landscape composition affects these behaviours. We conducted our research across seven study areas in northern Italy from December 2020 to November 2022, utilising camera trapping, faeces analysis, and sett surveys. Our findings revealed significant dietary variation, with earthworms being the primary food source in natural landscapes, while fleshy fruits being consumed especially in mixed and heavily modified landscapes, up to constitute the staple of the diet in one agricultural area. Badgers were found to be nocturnal, primarily active between sunset and sunrise. Setts varied considerably in structure and location, with a preference for natural grounds over human-made structures; key factors influencing sett site choice included slope, exposure, and vegetation cover. This study underscores the European badger’s remarkable adaptability, illustrating how its diet, activity patterns, and sett site preferences are shaped by a complex interplay of factors, allowing the species to thrive in both pristine and modified environments across northern Italy.

Divergent seed dispersal outcomes: Interactions between seed, disperser, and forest traits.

Animals disperse seeds in various ways that affect seed deposition sites and seed survival, ultimately shaping plant species distribution, community composition, and ecosystem structure. Some animal species can disperse seeds through multiple pathways (e.g., defecation, regurgitation, epizoochory), each likely producing distinct seed dispersal outcomes. We studied how seed traits (size and toughness) interact with disperser species to influence seed dispersal pathway and how this ultimately shapes the proportion of seeds deposited in various habitat types. We focused on three frugivorous species of duikers (African forest antelopes) in the Dja Faunal Reserve, a tropical rainforest in southern Cameroon. Duikers can both defecate and regurgitate seeds, the latter predominantly occurring during rumination at their bedding sites (or "nests"). We located duiker nests and dungs along 18 linear 1-km-transects to assess: (1) how seed traits affect the likelihood of dispersal via defecation versus regurgitation, (2) if defecated versus regurgitated seeds are deposited at different rates in different forest types (assessed by indigenous Baka), microhabitats, and forest structural attributes (measured by drone lidar), and (3) if these differ between three duiker species that vary in size and diel activity patterns. We found that duikers predominantly defecated small seeds (<3 mm length) and regurgitated larger and tougher seeds (>10 mm length), the latter including 25 different plant species. The three duiker species varied in their nesting habits, with nocturnal bay duikers (Cephalophus dorsalis) nesting in dense understory vegetation at proportions 3-4 times higher than Peter's and yellow-backed duikers (Cephalophus callipygus and Cephalophus silvicultor). As a result, bay duikers deposited larger regurgitated seeds at a higher rate in habitats with denser understory where lianas and palms predominate and near fallen trees. This directed regurgitation seed deposition likely plays an important and unique role in forest succession and structure. This study highlights the importance of ungulate seed dispersal by regurgitation, a vastly understudied process that could impact many ecosystems given the prevalence of ruminating ungulates worldwide.

Camera Traps Reveal Variation in Diel Activity Patterns among Different Sex-Age Classes in Brown Bears in Hokkaido

Camera Traps Reveal Variation in Diel Activity Patterns among Different Sex-Age Classes in Brown Bears in Hokkaido

Thermal constraints and gender-related differences in the activity patterns of the monomorphic rodent Clyomys laticeps

Abstract The daily activity pattern of animals can be classified as diurnal, nocturnal, crepuscular, and cathemeral reflecting strategic decisions to maximize mating and foraging while reducing predation risks and thermal constraints. Among monomorphic mammals, competition for resources and gender-related differences in physiology and reproductive strategies may translate into different activity patterns of males and females. Therefore, to understand the daily activity pattern both aboveground and belowground of the semifossorial rodent Clyomys laticeps, we tested the following hypotheses: (1) males and females differ in their diel activity patterns; (2) males are active for longer periods than females due to a promiscuous mating system and female site fidelity; and (3) higher maximum temperatures restrain C. laticeps activity. The study was carried out in the Serra de Caldas Novas State Park (Goiás, Brazil) in the Cerrado biome. The activity of C. laticeps was recorded using the telemetry technique over 5 days and nights (twice in each season, rainy and dry, between 2019 and 2021). Clyomys laticeps activity was bimodal, with 2 peaks around dawn and dusk, resembling a crepuscular pattern. Temporal segregation in male and female activity patterns was restricted to the dry season, when female activity was more diurnal than males who were mainly nocturnal. Intersexual competition for resources or male-avoidance behavior by females during the dry food scarcity season could contribute to this pattern, although it may also be explained by gender-related differences in thermal tolerances. Overall, males were active for longer periods than females, probably as a strategy to increase mating opportunities among the former and site fidelity in the latter. Finally, temperature imposed major constraints on C. laticeps activities who preferred milder temperatures and avoided being active in temperatures above their thermoneutral zone.

Is the diel cycle of routine metabolic rate in mummichog (Fundulus heteroclitus) affected by near-infrared lighting used for visualizing behavior of fishes at night?

The metabolic rate of a freely moving fish (routine metabolic rate) is tightly coupled with volitional movement (spontaneous activity), both of which commonly show strong daily cycles linked to the species-specific diel activity pattern. Mummichog (Fundulus heteroclitus), an important estuarine fish in the north western Atlantic Ocean, are historically reported as diurnal (i.e., more active during daylight). Our recent laboratory studies on a Bay of Fundy population, however, showed a free-running (i.e., similarly active daytime and night-time) or even nocturnal (i.e., more active at night-time) diel activity pattern. In the laboratory, near-infrared (NIR) illumination is commonly used with a NIR-sensitive camera to visualize fish activity across the light-dark periods of the day. Because NIR light is close to the visible light spectrum and certain fishes show sensitivity to NIR, the use of NIR with mummichog possibly could disturb the animals and obscure the identification of their true diel activity pattern. We aimed to determine if NIR illumination (940 nm wavelength) influences the diel activity pattern of mummichog. We used measurements of routine metabolic rate (oxygen consumption rate, MO2) as a proxy for activity, as evaluating the effect of NIR requires treatments where NIR lights are off, which precludes visualization and direct assessment of fish activity at night-time. We measured routine MO2 of mummichogs over 6 days, exposed to either NIR off-on-off (2 days for each off or on period) or the opposite sequence of NIR on-off-on (to control for time-dependent effects). NIR lights did not influence the diel cycle of routine MO2, and activity by proxy, in mummichog. Thus, NIR illumination is a suitable method to visualize mummichog during light-dark diel cycles. Routine MO2, and presumably activity, was similar or higher during night-time periods compared to daytime periods, confirming a free-running or nocturnal activity pattern for at least certain populations of mummichog.

Detection rates and diel activity patterns of four understudied felids from Borneo.

Carnivore guilds are charismatic and have vital and irreplaceable roles in their native ecosystems, yet many of these species are threatened and remain understudied. Borneo is a biodiversity hotspot that hosts a rich diversity of endemic wildlife but is threatened by deforestation and habitat loss. Using cameras placed by the Smithsonian Institution in Sabah, Borneo, we assessed the detection rates and diel activity patterns of the native felid species. Across 51 camera trap sites between 2016 and 2019, felids were detected 55 times across a combined 9958 trap nights, including 20 independent detection events for Sunda leopard cats, 15 for Sunda clouded leopards, 12 for Borneo bay cats, and 5 for marbled cats, with no detections of flat-headed cats. Collectively, this demonstrates the challenge of sampling cryptic species that have declined due to habitat loss and conflict with humans. Despite this, we show that Borneo bay cats and marbled cats exhibited different diel activity patterns than Sunda cloud leopards, suggesting the smaller species use temporal displacement to avoid competition and predation. Sunda leopard cats exhibited broadly similar activity patterns to Sunda clouded leopard, potentially because the two species typically occupy different dietary and habitat niches. These results demonstrate the importance of devoting future research towards monitoring these species and understanding the mechanisms by which they co-exist.

First insights into the vertical habitat use of young porbeagles in the north-western Atlantic with implications for bycatch reduction strategies

Context For threatened marine species, data on their vertical habitat use patterns can reveal risk of interactions with fishing gear and can inform bycatch avoidance strategies. Such data are lacking for young porbeagles (Lamna nasus), which are captured as bycatch in north-western Atlantic fisheries. Aims We aimed to examine temporal patterns in diving and characterise vertical habitat use of young porbeagles during summer and autumn. Methods We used data from short-term (28-day), high-resolution (5-min interval) pop-off satellite tags attached to 14 young (young-of-the-year and 1-year-old) porbeagles to model depth use. Key results Occupied depths ranged from the sea surface to 679 m, with ambient water temperatures of −0.2 to 26°C. Diel period and season were factors related to depth use. Conclusions Sharks exhibited a diel activity pattern characterised by more extensive use of the water column during the day while remaining primarily at the surface at night. Depth use differed between seasons, with summer characterised by greater affinity for surface waters (0–10 m) compared to autumn. Implications Young porbeagles are at risk of interaction with active fisheries on the continental shelf, but interactions may be reduced by setting gear deeper at night or during summer.

The Diel Activity Pattern of Haemaphysalis longicornis and Its Relationship with Climatic Factors.

Haemaphysalis longicornis is one of the most medically important carriers of various pathogens. Although H. longicornis is an important vector, only basic ecological and biological information has been obtained, primarily focusing on its abundance and distribution. This study determined the most active time and meteorological conditions for the diel activity of H. longicornis. The diel activity pattern of H. longicornis was the highest between 10:00 and 14:00, and the lowest between 22:00 and 02:00. The major activity temperature of H. longicornis was between 25 °C and 40 °C, with the highest activity at 35 °C. The relative humidity was between 30% and 70% during the active period. Temperature had the highest correlation with diel activity (R = 0.679), followed by humidity (R = -0.649) and light intensity (R = 0.572). Our results provide basic information for the development of tick-borne disease vector control programs and tick surveillance.

Assessing the potential of camera traps for estimating activity pattern compared to collar‐mounted activity sensors: a case study on Eurasian lynx Lynx lynx in south‐eastern Norway

The diel activity patterns of animals convey information about physiology, ecological niches and animal behaviour relevant for both applied conservation and more theoretical research. However, these patterns are challenging to study in the field. The current gold‐standard approach to quantify movements and activity patterns of medium to large wildlife species is to use global positioning systems (GPS) collars equipped with activity sensors (e.g. accelerometers). A more recent approach consists of inferring activity patterns from the time‐stamped pictures of wildlife obtained from camera traps now routinely used in wildlife monitoring projects. However, few studies have attempted to validate estimates of activity patterns obtained from camera traps against those obtained from activity sensors. In this study, we compared the diel activity pattern of the Eurasian lynx Lynx lynx inferred from detections by a network of over 300 camera traps active between 2010 and 2020, to activity patterns obtained from 18 GPS‐collared lynx (8 females, 10 males) equipped with 2‐axis accelerometer sensors, in the same area of southern Norway. Our results suggest that camera traps can be used to estimate diel activity curves that are comparable to those obtained from accelerometers. In our study, 75 detections were sufficient to approximate the diel activity pattern obtained from accelerometer. Subsampling indicated that a low number of detections results in a coarser approximation of the diel activity pattern.

Seasonal activity patterns and home range sizes of wolves in the human‐dominated landscape of northeast Türkiye

Gray wolves Canis lupus comprise one of the most widely distributed carnivore species on the planet, but they face myriad environmental and anthropogenic pressures. Previous research suggests that wolves adjust their time‐ and space‐use seasonally to mitigate risks from humans, conspecifics, and other predators while maximizing their hunting and reproductive success. With many populations of wolves resettling in areas with dense human populations, understanding how wolves may adjust their temporal and spatial patterns in these more human‐dominated landscapes is of high conservation importance. Typically, human presence causes wolves to increase their nocturnality and home range size. Here, we look at how seasonal home range size and diel activity patterns among resident and non‐resident wolves differ in an ecosystem that experiences significant differences in human activity between seasons. While non‐resident wolves had larger home ranges than resident wolves, there were no differences in home range sizes within residents and non‐residents between seasons, suggesting that seasonal changes in human presence had no effect on home range size. The activity patterns of wolves were similar between seasons, but resident wolves had greater overlap with humans and were more active than non‐resident wolves when humans were less present in the landscape. Both resident and non‐resident wolves showed increased nocturnality, with both groups selecting for nocturnality more strongly in the nomadic season. This is the first study of tracking Türkiye's wolves and offers the first descriptions of the temporal and spatial trends of GPS‐collared wolves in this highly human‐dominated environment.

Artificial light at night drives diel activity patterns of synanthropic pipistrelle bats and their prey

The use of artificial light at night (ALAN) has increased drastically worldwide over the last decades. ALAN can have major effects on nocturnal communities, including insects and bats. Insects are attracted to street lights and few bat species take advantage of this by foraging on the attracted insects. ALAN potentially affects the temporal patterns of insect abundance and thereby bat foraging behaviour. In a natural dark environment, these patterns are usually bimodal, with an activity peak in the early evening and the morning. Little is known about how ALAN affects insect presence throughout the night, and whether the light spectrum plays a role. This is important, as these temporal changes may be a key driver of disturbances in bat-insect interactions. Here, we studied how white and red light affect insects' and bats' nightly activity patterns. The activity of insects and bats (Pipistrellus spp.) was recorded throughout the night at seven experimentally illuminated sites in a forest-edge ecosystem. ALAN disrupted activity patterns, with both insects and bats being more active throughout the night. ALAN facilitated all-night foraging in bats especially near white light, but these effects were attenuated near red light. The ability to forage throughout the night may be a key advantage causing synanthropic bats to dominate in illuminated environments, but this could also prove detrimental in the long term. As red light reduced disturbing effects of ALAN on insects and bats diel activity pattern, it opens the possibility of using spectral composition as a mitigation measure.

A global dataset of diel activity patterns in insect communities

Insect activity powers ecosystems and food production globally. Although insect activity is known to vary with the rise and setting of the sun, there is surprisingly limited empirical information on how insect abundance and richness varies across the 24-hour day–night (diel) cycle. Moreover, commonly used methods for sampling insects such as light traps do not provide suitable comparisons of community properties between diel periods. We present a dataset of 1512 observations of abundance and richness during diurnal and nocturnal periods in insect communities worldwide. The data were collected from 99 studies that systematically sampled insect communities during day and night, using sampling methods minimally influenced by diel variation, such as movement-based interception traps. Spanning six continents, 41 countries and 16 insect orders, the data can support investigations into the factors influencing insect diel preferences as well as the causes and consequences of temporal changes in insect biodiversity. The data also provides key baseline information on the diel activity patterns of insect communities for long-term ecological monitoring. These pursuits take on added significance considering contemporary ‘insect declines’ and increasing anthropogenic impacts on diurnal and nocturnal biodiversity.

Habituation of wildlife to ecotourism: A COVID‐19 lockdown experiment in Corcovado National Park, Costa Rica

AbstractCorcovado National Park (CNP) in Costa Rica is an important destination for ecotourism. However, the effects of increasing human visitation on wildlife needed evaluation and the global COVID‐19 pandemic lockdown provided a scenario to test the effects of tourist activity on wildlife presence and activity. We performed a camera trap survey initiated during the COVID‐19 lockdown and continuing when tourism resumed (Oct 2020–May 2021). We deployed camera traps on walking trails, including those that remained closed to tourists at all times (control) and those open to tourists after the lockdown was lifted (experimental). With an effort of 2312 trap nights, we assessed the photo rates and diel activity patterns of humans, 11 other species of mammals, and two species of birds. Our results suggest that wildlife species were already habituated to tourists in this area, and thus their behavior and activity did not change after the lockdown was lifted.

Human avoidance, selection for darkness and prey activity explain wolf diel activity in a highly cultivated landscape

Wildlife that share habitats with humans with limited options for spatial avoidance must either tolerate frequent human encounters or concentrate their activity into those periods with the least risk of encountering people. Based on 5259 camera trap images of adult wolves from eight territories, we analyzed the extent to which diel activity patterns in a highly cultivated landscape with extensive public access (Denmark) could be explained from diel variation in darkness, human activity, and prey (deer) activity. A resource selection function that contrasted every camera observation (use) with 24 alternative hourly observations from the same day (availability), revealed that diel activity correlated with all three factors simultaneously with human activity having the strongest effect (negative), followed by darkness (positive) and deer activity (positive). A model incorporating these three effects had lower parsimony and classified use and availability observations just as well as a ‘circadian' model that smoothed the use‐availability ratio as function of time of the day. Most of the selection for darkness was explained by variation in human activity, supporting the notion that nocturnality (proportion of observations registered at night vs. day at the equinox) is a proxy for temporal human avoidance. Contrary to our expectations, wolves were no more nocturnal in territories with unrestricted public access than in territories where public access was restricted to roads, possibly because wolves in all territories had few possibilities to walk more than few hundred meters without crossing roads. Overall, Danish wolf packs were 6.5 (95% CI: 4.6–9.6) times more active at night than at daylight, which make them amongst the most nocturnally active wolves reported so far. These results confirm the prediction that wolves in habitats with limited options for spatial human avoidance, invest more in temporal avoidance.

Comparing the effectiveness of adulticide application interventions on mitigating local transmission of dengue virus

AbstractThe southern US has a large presence of mosquito vector species for dengue virus (DENV) and experiences thousands of DENV importations every year, which have led to several local outbreaks. Adulticide spraying targeting active mosquitoes is one of the most common insecticide strategies used as a response to an outbreak. The aim of this study is to evaluate the effectiveness of adulticide spraying conducted at different times of the day to curb DENV transmission. Based on unique dataset of Aedes aegypti diel activity patterns in Miami-Dade County, Florida, and Brownsville, Texas, we developed a mechanistic model of DENV transmission, which simulates adulticide spraying interventions. We estimated that spraying adulticide for 14 consecutive days at 7am or 8 pm was highly effective in reducing DENV outbreak probability from 10% in the absence of interventions to 0.1% for Miami-Dade County, and from 7.8 to 0.1% for Brownsville. Moreover, in case of a local outbreak in Miami-Dade County, we estimated the median number of symptomatic infections after the identification of a local outbreak to be reduced from 67.0 (IQR: 25.5–103.0) in the absence of interventions to 1.0 (IQR: 0.0–2.0) when spraying adulticide for 14 consecutive days at 8 pm. In Brownsville, the same intervention is estimated to lead to a decrease from 15.0 (IQR: 7.0–33.0) cases to 1.0 (IQR: 0.0–2.0). Our study highlights the importance of considering diel activity patterns of vector mosquito species in arbovirus preparedness and response planning and provide quantitative evidence to guide the decision-making of mosquito control authorities.

Diel activity patterns of a canopy-inhibiting beetle community (Coleoptera) in a Neotropical rainforest

Diel activity is one main feature of animal‘s behavior and is often an intrinsic trait characterizing distinct taxonomic groups. Abiotic conditions such as temperature may influence the diel activity patterns of arthropod communities associated with a particular ecosystem or habitat. Similarly, biotic factors, such as resource availability, affect arthropod activity. In addition, diel activity is thought to be an important factor in niche partitioning of arthropod communities. As part of a larger beetle survey in a lowland tropical rainforest in southern Venezuela, I analyzed the diel activity of an arboreal beetle community collected from 23 canopy-tree species over a cumulative year. Diel activity was observed in 535 beetle species, comprising 5,948 individuals, using a canopy crane installed in the study area. Of the 535 beetle species, 198 (37%) showed diurnal activity, and 281 (52.5%) showed nocturnal activity. In contrast, the proportions of nocturnal (n = 2,024, 34%) and diurnal (n = 1,983, 33.3%) individuals were balanced. Most of the observed beetles occurred only during the activity phase in their host trees. This particularly applies to extrafloral nectary- and flower-visiting beetle species. Flowering trees attracted different proportions of diurnal and nocturnal species according to flowering syndrome, whereas extrafloral nectaries were mainly visited at night. Thus, the beetle communities associated with single tree species showed distinct compositions of nocturnal and diurnal species.

Midnight siesta: Bimodal temporal activity observed in an endangered marsupial predator

AbstractUnderstanding animal behavioural patterns can provide insight into how populations and communities are adapting to broader environmental shifts. The northern quoll (Dasyurus hallucatus), an endangered marsupial predator, has traditionally been classified as nocturnal. However, evidence is emerging that such simple classifications belie the complexity of animal activity patterns. Using time‐stamped camera trap imagery and fine‐scale accelerometer data, our study explores the diel activity patterns of northern quolls across their range in northern Australia. Contrary to the conventional nocturnal classification, we found that the northern quoll used bimodal activity patterns in four of the five populations examined in this study. Activity and accelerometer data showed two nightly movement peaks, with a distinctive lull around midnight, a pattern similar to one displayed by other marsupial predators. We found no consistent effect of season or lunar phase on temporal activity. Instead, its possible temporal activity patterns are primarily influenced by factors not accounted for here, such as prey availability, climate, predator avoidance, or energy expenditure related to digestion. We suggest further research incorporating these factors will improve our understanding of northern quoll behaviour.

Ultrasound and ultraviolet: crypsis in gliding mammals.

Gliding is only present in six extant groups of mammals-interestingly, despite divergent evolutionary histories, all mammalian gliders are strictly nocturnal. Gliding mammals also seem to have relatively high rates of ultrasound use and ultraviolet-induced photoluminescence (UVP) in contrast with their close relatives. Therefore, we hypothesized that, despite diverging lineages, gliding mammals use similar modes of cryptic communication compared to their non-gliding counterparts. We developed two datasets containing the vocal range (minimum-maximum of the dominant harmonic; kHz) and UVP of 73 and 82 species, respectively; we report four novel vocal repertoires and 57 novel observations of the presence or absence of UVP. We complemented these datasets with information about body size, diel activity patterns, habitat openness, and sociality to explore possible covariates related to vocal production and UVP. We found that the maximum of the dominant harmonic was significant higher in gliding mammals when vocalizing than their non-gliding relatives. Additionally, we found that nocturnality was the only significant predictor of UVP, consistent with the previous hypothesis that luminophores primarily drive UVP in mammal fur. In contrast, however, we did not find UVP ubiquitous in nocturnal mammals, suggesting that some unknown process may contribute to variation in this trait.