Food Manipulation Research Articles

The skin of birds' feet: Morphological adaptations of the plantar surface

The skin of the foot provides the interface between the bird and the substrate. The foot morphology involves the bone shape and the integument that is in contact with the substrate. The podotheca is a layer of keratinized epidermis forming scales that extends from the tarsometatarsus to the toe extremities. It varies in size, shape, amount of overlap and interacts with the degree of fusion of the toes (syndactyly). A study of toe shape and the podotheca provides insights on the adaptations of perching birds. Our analysis is based on micro-CT scans and scanning electron microscopy images of 21 species from 17 families, and includes examples with different orientations of the toes: zygodactyl (toes II and III forward), anisodactyl (toes II, III, and IV forward), and heterodactyl (toes III and IV forward). We show that in these three groups, the skin forms part of a perching adaptation that involves syndactyly to different degrees. However, syndactyly does not occur in Psittacidae that use their toes also for food manipulation. The syndactyly increases the sole surface and may reinforce adherence with the substrate. Scale shape and toe orientation are involved in functional adaptations to perch. Thus, both bone and skin features combine to form a pincer-like foot.

Food safety knowledge, food shopping attitude and safety kitchen practices among Romanian consumers: A structural modelling approach

This paper aimed to establish the relationship between food safety knowledge, food shopping attitude, and self-reported kitchen practices among Romanian consumers. The study used data collected in an online survey applied on 985 consumers. A knowledge, attitude and practice (KAP) model applied by structural equation modelling revealed significant correlations between knowledge and attitude (r = 0.36; p < 0.001). Also, knowledge and attitude depicted significant effects on self-reported safety kitchen practices (β = 0.17, p < 0.001; β = 0.47, p < 0.001) and explained 30% of the variance of the food safety practices applied by Romanian consumers. These findings suggest that higher levels of food safety knowledge than current ones could conduct to an improved attitude towards food shopping priorities and could incline consumers to adopt adequate food safety practices during food purchasing in shops and food manipulation in their kitchens. Case-studies from real life situations (an observational study including 15 Romanian households) support the findings of this study and urge interventions to improve consumers’ food safety practices at home.

Food Safety Conditions in Home-Kitchens: A Cross-Sectional Study in the Federal District/Brazil.

This study aimed to analyze the food safety conditions in home kitchens from the Brazilian Federal District. A previously validated instrument composed of 77 items (in four blocks) was used to evaluate the safety conditions in home kitchens. A survey was carried out with on-site application with 226 home kitchens’ food handlers in the Federal District, Brazil to evaluate Brazilian home kitchens’ good practices. Of the home kitchen food handlers, most of them were female (64.6%), had completed undergraduate education (29.2%), and were 45–59 years old (23.5%). The visited households had an average of 3.38 ± 1.48 residents that ate some of their meals at home, and 40% declared the monthly family income to be between 5 and 15 Brazilian minimum wages (MW). Regarding the reliability of the instrument, from the KR-20 test, it was verified that the instrument presents good internal consistency (α = 0.758). According to the instrument classification, the home kitchens’ sample was considered as at a medium risk of food contamination (46.5% of them presented from 51 to 75% of conformities to the instrument). There was a statistical difference between house-kitchens with a family income from zero to one minimum wage (MW) and those receiving from 5 to 15 MW (p = 0.017), as well as between those from zero to one MW and who earn above 15 MW (p = 0.009). The result of the on-site evaluation shows that the instrument was able to measure food safety conditions in Brazilian Federal District domestic kitchens. Such findings can contribute positively to the development of actions in health education that help in the adoption of good practices of food manipulation and, consequently, in the reduction in foodborne disease outbreaks in residences.

Resource trait specialisation in an introduced fish population with reduced genetic diversity

Ecological specialisation is hypothesised to play a major role in the evolution of phenotypic diversity, especially following the colonisation of novel habitats. For example, cichlid fishes provide some of the most remarkable evidence for rapid ecological diversification. Here, we capitalised on a recently (≤ 40 years ago) introduced population of red devils (Amphilophus labiatus) in Australia to investigate adaptive phenotypic responses to a novel environment. We used stomach content analyses, morphometrics and laboratory experiments to test for covariation between diet and size of an important trophic trait, lip size. We found that, while maximum lip size in the study population was smaller than in the species’ natural range, the proportions of algae, insects and fish remains in the diet covaried with lip size. However, contrary to predictions, we found no evidence for lip development to be plastic under laboratory conditions in relation to substrate complexity or food manipulation, nor did we find any relationship between lip morphology and feeding performance in adults. Single nucleotide polymorphism data, in turn, suggested that the introduced population has reduced standing genetic variation, which potentially influences both phenotypic plasticity and diversity, in comparison to native populations. Together, the results suggest that morphological variation in a key trophic trait can respond rapidly to diet in a novel environment, despite reduced genetic diversity in the population.

Tetracycline resistance transmission in Campylobacter is promoted at temperatures resembling the avian reservoir

Campylobacter is the causal agent of campylobacteriosis in humans, a self-limiting gastroenteritis. Campylobacteriosis is a zoonosis, commonly transmitted from contaminated chicken meat by either direct consumption or cross contamination during food manipulation. Presence of plasmids encoding for resistance to antibiotics such as tetracycline is common among Campylobacter isolates. In this report, we studied the effect of the temperature in the conjugation frequency of several tet(O) carrying plasmids, providing tetracycline resistance to the recipient cells. The conjugation frequency from donor cells carrying three previously characterized plasmids (pCjA13, pCjA9 and pTet) and from two clinical isolates was determined. Two temperatures, 37 and 42 °C, mimicking the conditions encountered by C. jejuni in the human and broiler chicken gastrointestinal tracts, respectively, were assessed. Our results clearly indicate that the conjugation process is promoted at high temperature. Accordingly, the transcriptional expression of some putative conjugative apparatus genes is thermoregulated, being induced at 42 °C. The two plasmids present in the clinical isolates were sequenced and assembled. Both plasmids are highly related among them and to the pTet plasmid. The high identity of the genes putatively involved in the conjugation process among the plasmids is in agreement with the similar behavior regarding the temperature dependency of the conjugative process. This report suggest that conjugation of plasmids carrying antibiotic resistance genes occurs preferentially at temperatures that resemble the gastrointestinal tract of birds, the main reservoir of C. jejuni.

Juvenile diet quality and intensity of sexual conflict in the mite Sancassania berlesei

BackgroundDiffering evolutionary interests of males and females may result in sexual conflict, whereby traits or behaviours that are beneficial for male reproductive success (e.g., traits related to male-male competition) are costly for females. Since sexual conflict may play an important role in areas such as speciation, population persistence or evolution of life history traits, understanding what factors modulate the intensity of sexual conflict is important. This study aims to examine juvenile diet quality as one of the underestimated ecological factors that may affect the intensity of sexual conflict via individual conditions. I used food manipulation during the development of the mite Sancassania berlesei to investigate the effects on male reproductive behaviour and competitiveness, male-induced harm to female fitness and female resistance to this harm.ResultsMales that were exposed to low-quality food started mating later than the control males, and number of their mating attempts were lower compared to those of control males. Moreover, males from the low-quality diet treatment sired fewer offspring under competition than males from the control treatment. However, the fitness of females exposed to males reared on a poor diet did not differ from that of females mated with control males. Furthermore, female diet quality did not alter their resistance to male-induced harm.ConclusionOverall, diet quality manipulation affected male reproductive behaviour and mating success. However, I found no evidence that the intensity of sexual conflict in S. berlesei depends on male or female conditions. Investigating a broader range of environmental factors will provide a better understanding of sexual conflict dynamics and its feedback into associated evolutionary mechanisms.

Divergent strategies in faeces avoidance between two cercopithecoid primates.

Parasites constitute a major selective pressure which has shaped animal behaviour through evolutionary time. One adaption to parasites consists of recognizing and avoiding substrates or cues that indicate their presence. Among substrates harbouring infectious agents, faeces are known to elicit avoidance behaviour in numerous animal species. However, the function and mechanisms of faeces avoidance in non-human primates has been largely overlooked by scientists. In this study, we used an experimental approach to investigate whether aversion to faeces in a foraging context is mediated by visual and olfactory cues in two cercopithecoid primates: mandrills (Mandrillus sphinx) and long-tailed macaques (Macaca fascicularis). Visual and olfactory cues of faeces elicited lower food consumption rates in mandrills and higher food manipulation rates in long-tailed macaques. Both results support the infection-avoidance hypothesis and confirm similar tendencies observed in other primate species. More studies are now needed to investigate the divergence of avoidance strategies observed in non-human primates regarding food contamination.

Developmental and age-related changes in sensorimotor regulation of biting maneuvers in humans

Previous studies indicated distinct differences in biting and chewing behaviors between children and adults. However, these studies used different methodologies and failed to study age-related changes in the fine motor control of biting from childhood to adulthood. Therefore, this study aimed to investigate age-related changes in oral fine motor control in healthy children in comparison to adults. Sixty-five healthy children (3–17 years) were equally divided into five age-groups based on their dental eruption stages. Each participant was asked to hold half a peanut rested on a force transducer between two opposing anterior teeth for 3–4 s before splitting it. The force applied on the transducer was continuously monitored and recorded during food holding and splitting. The data obtained from the children subgroups were compared to an adult group (18–35 years). Results showed that the force regulation during food manipulation was higher and more variable in children with primary to early-permanent dentition stages compared to adults. Additionally, children with primary and early-mixed dentition showed longer food splitting duration than adults and exhibited a predominantly step-wise ramp-increase of force. The results of the present study showed age-related changes in fine motor control of food biting maneuvers. The results of the study also suggested that younger children with primary dentition show signs of immature oral fine motor control. However, with an increase in age and the accompanying structural changes, the oral fine motor control eventually transits to a more matured “adult-like” biting maneuvers.

Unilateral hypoglossal nerve and recurrent laryngeal nerve weakness following endotracheal intubation

Endotracheal intubation with cuffed tube is a safe procedure associated with few complications in majority of patients. Immediate complications are primarily associated with problems dring intubation and extubation while early and late complications represent the short- and long-term effets of epithelial trauma. True vocal cord paralysis may follow endotracheal intubation and be the result of peripheral nerve damage. This damage can occur as the result of compressing the nerve between an inflated endotracheal tube cuff and the overlying thyroid cartilage.1 The hypoglossal nerve (12th cranial nerve) is motor nerve. It supplys the tongue muscle and help in speech, Food manipulation, and swallowing. Hypoglossal nerve injury following endotracheal intubation under general anesthesia is a rare complication and can cause symptoms, such as dysarthria and dysphagia.2

Anatomical and scanning electron microscopic study of the tongue in the African giant pouched rats (Cricetomys gambianus, Waterhouse)

The African giant pouched rat is a nocturnal, fossorial and omnivorous wild rodent widely distributed in sub-Saharan Africa. The morphology of lingual surface has not previously examined and was investigated by gross dissection, stereomicroscopy, scanning electron and light microscopy. Grossly, it was elongated and dorso-ventrally flattened with rounded tip. It measured 3.48±0.33cm in length, with a median groove of 1.4±0.1cm in length and well-developed lingual prominence. Stereomicroscopically, filiform, fungiform and vallate papillae were indicated in the apex, body and root. Fungiform papillae intermingled with filiform on the ventral and dorsal surface of the apex and body. Three vallate papillae were located in triangular arrangement on the root. The surface ultrastructural features distinguished four types of filiform which varied in size, shape and distribution: first type with long pointed process was preponderant on the apex and body of tongue; the second with robust base was located on central lingual prominence; the third (caudal body) was conically shaped with pointed process; and the fourth type (root) had forked filamentous process. Large oval-shaped fungiform papillae were apparent. Each vallate was surrounded by a circumferential groove into which taste pores opened. Histologically, the tongue surface displayed moderately keratinized stratified squamous epithelium, and lamina propria that varied in places. Fungiform and vallate showed spindle-shaped taste buds. Serous and mucous acini containing neutral and acidic mucins were observed in lamina propria of root. The structural adaptations of the tongue to omnivorous diet and food manipulation in oral cavity were comparatively discussed.

Probabilistic model for the estimation of the consumer exposure to methicillin-resistant Staphylococcus aureus due to cross-contamination and recontamination.

The presence of multidrug‐resistant bacteria like methicillin‐resistant Staphylococcus aureus (MRSA) in retail meat is one of the current concerns of the public health authorities. Bacterial cross‐contamination and recontamination during household food preparation could play an important role in the dissemination of such bacteria, and therefore could contribute to a serious health problem, more specifically for immunocompromised people. In order to evaluate the importance of such events, a probabilistic model was developed to estimate the likelihood and extent of cross‐contamination and recontamination and the burden of MRSA from contaminated raw chicken meat via hands and kitchen utensils in a serving (consisting on a slice of bread and a piece of grilled chicken meat) during a household barbecue in Germany. A modular design was used, taking into account the chronological order of the routines during the barbecue event, and Monte Carlo simulations were applied. Available data on the prevalence and burden of MRSA in chicken meat at retail in Germany were used as starting point and were incorporated in the model as probability distributions. The probabilities and extent of bacterial transfer between food items and kitchen utensils (referred to as “Objects”) and the routines performed during food preparation (referred to as “Actions”) specified by their probabilities of occurrence were incorporated as the main input parameters. The model was set up in R 3.5.0 and converted to a standardized format (FSKX file). Therefore, the code can be easily accessed, evaluated, modified, and reused for different purposes. The present study contributes to the quantification of consumer exposure to MRSA through food consumption once contaminated food has entered the household kitchen. Even when the MRSA prevalence and bacterial load in retail chicken meat in Germany are low, resistant bacteria can reach the consumer due to cross‐contamination and recontamination events. The results show that the probability of one CFU to be transferred from the contaminated raw chicken meat to the final serving and the number of MRSA bacteria transferred due to cross‐contamination and recontamination events are in general low, being the contamination of the final serving more likely to occur via bread, rather than via grilled chicken. The results show that the prevalence of MRSA at retail highly influences the probability of the final serving to be contaminated. However, this study also highlights the importance of keeping good hygiene practices during the household food manipulation for reducing the spread of MRSA. The provision of the model in a standardized data format will allow an easy incorporation of the developed model into a complete quantitative microbial risk assessment model that will greatly help to estimate the risk of consumer exposure to MRSA through the consumption of contaminated food.

Independent replication of motor cortex and cervical spinal cord electrical stimulation to promote forelimb motor function after spinal cord injury in rats

Cervical spinal cord injury (SCI) impairs arm and hand function largely by interrupting descending tracts. Most SCI spare some axons at the lesion, including the corticospinal tract (CST), which is critical for voluntary movement. We targeted descending motor connections with paired electrical stimulation of motor cortex and cervical spinal cord in the rat. We sought to replicate the previously published effects of intermittent theta burst stimulation of forelimb motor cortex combined with trans-spinal direct current stimulation placed on the skin over the neck to target the cervical enlargement. We hypothesized that paired stimulation would improve performance in skilled walking and food manipulation (IBB) tasks. Rats received a moderate C4 spinal cord contusion injury (200 kDynes), which ablates the main CST. They were randomized to receive paired stimulation for 10 consecutive days starting 11 days after injury, or no stimulation. Behavior was assessed weekly from weeks 4–7 after injury, and then CST axons were traced. Rats with paired cortical and spinal stimulation achieved significantly better forelimb motor function recovery, as measured by fewer stepping errors on the horizontal ladder task (34 ± 9% in stimulation group vs. 51 ± 18% in control, p = .013) and higher scores on the food manipulation task (IBB, 0–9 score; 7.2 ± 0.8 in stimulated rats vs. 5.2 ± 2.6 in controls, p = .025). The effect size for both tasks was large (Cohen's d = 1.0 and 0.92, respectively). The CST axon length in the cervical spinal cord did not differ significantly between the groups, but there was denser and broader ipsilateral axons distribution distal to the spinal cord injury. The large behavioral effect and replication in an independent laboratory validate this approach, which will be trialed in cats before being tested in people using non-invasive methods.

Topographic study of human tongue in relation to oral tribology

Human tongue plays a critical role in food oral processing and in particular to food manipulation and texture sensation. We speculate that different topographic characteristics among human individuals could be a fundamental cause for different food oral behavior and sensory perception. We hypothesize that tongue surface roughness will influence oral lubrication and therefore texture sensation. As the first initiative, this work investigated surface profile of human tongue. Altogether 71 young Chinese subjects participated in this investigation. Double moulding using silicone rubber and followed by gypsum was applied for the replication of the surface microstructure of human tongue. Optical scanning was applied to obtain 3D data of the replicated tongue surfaces. Mountains Map software was used to analyze topographic features. The method was verified by specimen of standard surfaces as well as pig's tongue. Results show that human tongue is generally symmetrical along the central line, but varies across the different area of the tongue. Tongue tip is the roughest part of the tongue. The roughness of the tongue decreases gradually from the front to the back. The calculated arithmetic roughness of the tongue tip varies from 50 μm to 160 μm for the investigated subjects, with an arithmetic average Sa at 89.53 ± 20.48 μm and a square root average Sq at 114.80 ± 25.47 μm. A preliminary analysis showed a possible correlation between tongue surface roughness and oral lubrication.

Telocytes constitute a widespread interstitial meshwork in the lamina propria and underlying striated muscle of human tongue

Telocytes have recently emerged as unique interstitial cells defined by their extremely long, thin and moniliform prolongations termed telopodes. Despite growing evidence that these cells consistently reside in the stromal compartment of various organs from human beings, studies dealing with telocytes in structures of the oral cavity are scarce. Hence, the present morphologic study was undertaken to explore for the first time the presence and specific localization of telocytes within tissues of the normal human tongue, a complex muscular organ whose main functions include taste, speech, and food manipulation in the oral cavity. Telocytes were initially identified by CD34 immunostaining and confirmed by CD34/PDGFRα double immunofluorescence and transmission electron microscopy. CD34+/PDGFRα+ telocytes were organized in interstitial meshworks either in the tongue lamina propria or in the underlying striated muscle. Lingual telocytes were immunonegative for CD31, c-kit and α-SMA. Telopodes were finely distributed throughout the stromal space and concentrated beneath the lingual epithelium and around CD31+ vessels, skeletal muscle bundles/fibers, and intramuscular nerves and ganglia. They also enveloped salivary gland units outside the α-SMA+ myoepithelial cells and delimited lymphoid aggregates. These findings establish telocytes as a previously overlooked interstitial cell population worth investigating further in the setting of human tongue pathophysiology.

Ecological mechanisms can modify radiation effects in a key forest mammal of Chernobyl

AbstractNuclear accidents underpin the need to quantify the ecological mechanisms which determine injury to ecosystems from chronic low‐dose radiation. Here, we tested the hypothesis that ecological mechanisms interact with ionizing radiation to affect natural populations in unexpected ways. We used large‐scale replicated experiments and food manipulations in wild populations of the rodent, Myodes glareolus, inhabiting the region near the site of the Chernobyl disaster of 1986. We show linear decreases in breeding success with increasing ambient radiation levels with no evidence of any threshold below which effects are not seen. Food supplementation of experimental populations resulted in increased abundances but only in locations where radioactive contamination was low (i.e., below ≈ 1 μSv/h). In areas with higher contamination, food supplementation showed no detectable effects. These findings suggest that chronic low‐dose‐rate irradiation can decrease the stability of populations of key forest species, and these effects could potentially scale to broader community changes with concomitant consequences for the ecosystem functioning of forests impacted by nuclear accidents.

Towards Robotic Feeding: Role of Haptics in Fork-Based Food Manipulation

Autonomous feeding is challenging because it requires manipulation of food items with various compliance, sizes, and shapes. To understand how humans manipulate food items during feeding and to explore ways to adapt their strategies to robots, we collected a rich dataset of human trajectories by asking them to pick up food and feed it to a mannequin. From the analysis of the collected haptic and motion signals, we demonstrate that humans adapt their control policies to accommodate to the compliance and shape of the food item being acquired. We propose a taxonomy of manipulation strategies for feeding to highlight such policies. As a first step to generate compliance-dependent policies, we propose a set of classifiers for compliance-based food categorization from haptic and motion signals. We compare these human manipulation strategies with fixed position-control policies via a robot. Our analysis of success and failure cases of human and robot policies further highlights the importance of adapting the policy to the compliance of a food item.

Predicting Real-Life Eating Behaviours Using Single School Lunches in Adolescents.

Large portion sizes and a high eating rate are associated with high energy intake and obesity. Most individuals maintain their food intake weight (g) and eating rate (g/min) rank in relation to their peers, despite food and environmental manipulations. Single meal measures may enable identification of “large portion eaters” and “fast eaters,” finding individuals at risk of developing obesity. The aim of this study was to predict real-life food intake weight and eating rate based on one school lunch. Twenty-four high-school students with a mean (±SD) age of 16.8 yr (±0.7) and body mass index of 21.9 (±4.1) were recruited, using no exclusion criteria. Food intake weight and eating rate was first self-rated (“Less,” “Average” or “More than peers”), then objectively recorded during one school lunch (absolute weight of consumed food in grams). Afterwards, subjects recorded as many main meals (breakfasts, lunches and dinners) as possible in real-life for a period of at least two weeks, using a Bluetooth connected weight scale and a smartphone application. On average participants recorded 18.9 (7.3) meals during the study. Real-life food intake weight was 327.4 g (±110.6), which was significantly lower (p = 0.027) than the single school lunch, at 367.4 g (±167.2). When the intra-class correlation of food weight intake between the objectively recorded real-life and school lunch meals was compared, the correlation was excellent (R = 0.91). Real-life eating rate was 33.5 g/min (±14.8), which was significantly higher (p = 0.010) than the single school lunch, at 27.7 g/min (±13.3). The intra-class correlation of the recorded eating rate between real-life and school lunch meals was very large (R = 0.74). The participants’ recorded food intake weights and eating rates were divided into terciles and compared between school lunches and real-life, with moderate or higher agreement (κ = 0.75 and κ = 0.54, respectively). In contrast, almost no agreement was observed between self-rated and real-life recorded rankings of food intake weight and eating rate (κ = 0.09 and κ = 0.08, respectively). The current study provides evidence that both food intake weight and eating rates per meal vary considerably in real-life per individual. However, based on these behaviours, most students can be correctly classified in regard to their peers based on single school lunches. In contrast, self-reported food intake weight and eating rate are poor predictors of real-life measures. Finally, based on the recorded individual variability of real-life food intake weight and eating rate, it is not advised to rank individuals based on single recordings collected in real-life settings.

Morphology and microstructure of the tongue of the lesser bamboo rat (Cannomys badius)

AbstractThe first detailed morphological description of the tongue and lingual papillae of the lesser bamboo rat, a fossorial rodent distributed in Indochina, is presented. Twelve tongues were examined by light, stereo‐ and scanning electron microscopy. The elongated tongue possessed an intermolar prominence and terminated in a rounded apex with a median sulcus. The dorsal surface of the tongue bore three types of papillae: filiform, fungiform and vallate, the first two of which were also observed on the ventral lingual surface. The filiform papillae varied in form and arrangement depending on the tongue region, although the majority of them were multifurcate, fork‐like papillae. The fungiform papillae were randomly scattered among the filiform papillae, with the highest density and number of taste pores (up to 12) at the ventral lingual apex. On the posterior tongue, two oval vallate papillae with numerous taste buds on their lateral epithelium were surrounded by a circumferential trench into which the serous von Ebner's glands’ ducts opened. The mucosal surface of the lingual radix was uneven without papillae, but contained mucous openings of Weber's glands. The tongue and lingual papillae of the lesser bamboo rat are similar to those of the large bamboo rat and show structural adaptations to the diet and food manipulation.

On special issue “Robotic Manipulation of Food”

On special issue “Robotic Manipulation of Food”

Bimanual Food Manipulation by Locusts Feeding on Loose Food

Holding food bimanually for biting off pieces with the mouth is a behavior performed by several groups of insects with predatory or plant eating habits. Locusts often grab longer pieces of loose or dangling grass with their forelegs and eat it in repetitive movement patterns by holding the blade vertical between the opposed tarsal pads. Head and body remain still while the mouthparts bite off and ingest suitable pieces. The forelegs alone raise and guide the grass blade precisely between the mandibles that bite across it in series of 1–5 consecutive biting bouts. A typical series has 3–4 bouts and cuts a 5-7 mm wide blade completely. The remaining edge of the grass blade is skewed at about 30–60 degrees. Consecutive series start with biting into the upper edge of the blade after the forelegs have pulled it nearer and under the mouthparts. During the first bites both legs extend forward moving the opposed tarsi along the blade and renew their grip more outward. The whole stereotyped but adaptive pattern involves only forelegs and mouthparts, while the palps continuously monitor the food’s shape and relative position to the mouthparts. In this first study of bimanual (“bi-tarsal”) food handling in insects the standard sequence of movements and muscle coordination of the forelegs is described for locusts. This repetitive behavior is an example of object-centered coordination between several appendages within the peripersonal space of animals.