Larger Felids Research Articles

A NEW SEMI-QUANTITATIVE METHOD FOR CODING CARNIVORE CHEWING DAMAGE WITH AN APPLICATION TO MODERN AFRICAN LION-DAMAGED BONES

ABSTRACT The ability to distinguish between the taphonomic patterns inflicted by different carnivore taxa in the fossil record is currently underdeveloped. Previous efforts to identify taxon-specific taphonomic damage to prey bones inflicted by larger felids have largely focused on tooth marks. Recent work, however, which considers patterns of chewing damage are only beginning to yield methods that can consistently distinguish between species, or even families, of large predators. Here we present a new low-cost, low-tech, semi-quantitative method for coding carnivore-inflicted chewing damage patterns using a basic 5-stage scale (0 = no damage, 1 = tooth marks only, 2 = minimal chewing damage, 3 = moderate chewing damage, 4 = severe chewing damage, fragmentation, or destruction), including a photographic guide to different levels of bone damage inflicted on different skeletal elements and portions. An independent test of this method by three experienced taphonomic analysts indicates that this method is easy to use and results in consistent data across analysts. We also apply this method to document and describe the intensity of damage that free-ranging African lions inflicted on a sample of zebra bones. This method can be used in conjunction with efforts to distinguish taxon-specific tooth mark shapes or patterns to more confidently infer the identity of different predators based on their chewing damage.

Using camera traps to study the elusive European Wildcat Felis silvestris silvestris Schreber, 1777 (Carnivora: Felidae) in central Germany: what makes a good camera trapping site?

Camera traping is a widely used method to study the abundance and population density of elusive terrestrial animals. To make full use of this method, it is necessary to obtain high photographic capture rates of the target species. We examine what characteristics of camera trapping sites are associated with high photographic capture rates of European Wildcat Felis silvestris silvestris. We measured Wildcat capture rates across 25 camera trapping sites located in a 20km² study area within an unprotected low mountain range forest in central Germany. We measured the distance of each trapping site to the forest boundary, to the next watercourse, and to the next human settlement, and broadly defined the type of forest structure the site was located in. None of these site characteristics, however, predicted wildcat photographic capture success. We also examined the degree of human disturbance at the site, measured as the photographic capture rate of humans (including vehicles). Wildcats were detected at similar rates on dirt or gravel roads (heavily used by humans) as on soft-surfaced paths or logging trails (less frequently used by humans), and the degree of human disturbance across sites did not affect wildcat capture success. We, therefore, suggest that trail features such as course, curvature and width, or vegetation density along the trail are more important determinants of Wildcat capture success than habitat characteristics. We conclude that for European Wildcats, as for many larger felids, forest roads provide suitable camera trapping sites and that Wildcats are fairly tolerant towards human traffic on these roads.

Effective Mechanical Advantage Allometry of Felid Elbow and Knee Extensors

Larger terrestrial mammals have generally been found to use more extended limb postures, a mechanism which maintains muscular requirements at larger sizes by improving the effective mechanical advantage (EMA) of limb musculature. Felids, however, have been documented to maintain joint angles across body sizes. If felid morphology scales isometrically, it would mean larger felids have relatively weaker muscles, compromising locomotor activities. Here, we examine the allometric relationships between the EMA of the elbow and knee extensors and body mass, finding that the EMA of the triceps brachii and quadriceps muscles scale with positive allometry. When species-specific joint angles were used rather than felid-average joint angles, EMA scales to body mass with more positive allometry. When the scaling of the muscle and ground reaction force (GRF) lever arms were investigated individually the allometric signal was lost; however, the muscle lever arms generally have allometric slope coefficients that are consistent with positive allometry, while the GRF lever arms demonstrate negative allometric slope coefficients. This suggests there are subtle alterations to limb morphology allowing different felid species to achieve an increased EMA via distinctive mechanisms. The quadriceps EMA was found to scale with sufficient positive allometry to compensate for increases in size without alteration in muscular anatomy; however, this is not the case for the triceps brachii EMA. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:775-784, 2019. © 2018 Wiley Periodicals, Inc.

Allometry of Felid Knee and Elbow Effective Mechanical Advantage

Body size has a profound impact on animal locomotion because all terrestrial animals must support and move their mass against gravity. If large animals were isometrically scaled versions of smaller animals, then larger animals would have relatively weaker muscles and bones, as both are a function of area. The loads associated with locomotion however, are largely equivalent to body mass, a function of volume. To contend with this problem, larger animals have been observed to use more extended limb postures; increasing the effective mechanical advantage (EMA) of their muscles. Felids however, maintain the same limb posture across body sizes, suggesting they are not increasing EMA through limb extension. To investigate how felids maintain the same posture across body sizes we analyzed the relationship between the EMA of the triceps brachii and quadriceps and body mass in nine species of felids with kinematic data from the literature.Ulnae (n=37) and femora (n=30) of nine species of felids were surface scanned using a 3D NextEngine laser scanner. Linear measurements were taken on the tibia, patella, talus, calcaneus, navicular, third cuneiform and third metatarsal. Ulna and femur surface models were aligned in virtual space using anatomical and biomechanical axes. Triceps brachii EMA was calculated as the ratio of the muscle lever arm to the GRF lever arm, which were both collected on the ulna surface model. The quadriceps muscle and GRF lever arms were calculated using the femur surface models, linear measurements of limb and foot bones and kinematic data. Joint EMAs, muscle lever arms and GRF lever arms were regressed against body mass using PGLS regressions incorporating a phylogeny from 10kTrees. Pagel's λ was zero for all analyses, so data were reanalyzed using reduced major axis (RMA) regressions without phylogenetic information.The triceps brachii and quadriceps EMA scale to body mass with slopes of 0.15 and 0.13, respectively, indicating positive allometry, meaning that larger felids have a relatively greater EMA and suggesting that some aspect of felid joint morphology is altered. For both joints neither the muscle lever arms nor the GRF lever arms are statistically different from isometry, however the muscle lever arms generally trend toward positive allometry, while the GRF lever arms lean toward negative allometry. This indicates that either there are subtle changes to both lever arms or that different felid species accomplish an increased EMA in distinct ways.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

3D Morphometric and Posture Study of Felid Scapulae Using Statistical Shape Modelling

We present a three dimensional (3D) morphometric modelling study of the scapulae of Felidae, with a focus on the correlations between forelimb postures and extracted scapular shape variations. Our shape modelling results indicate that the scapular infraspinous fossa becomes larger and relatively broader along the craniocaudal axis in larger felids. We infer that this enlargement of the scapular fossa may be a size-related specialization for postural support of the shoulder joint.

Allometry and performance: the evolution of skull form and function in felids

Allometric patterns of skull-shape variation can have significant impacts on cranial mechanics and feeding performance, but have received little attention in previous studies. Here, we examine the impacts of allometric skull-shape variation on feeding capabilities in the cat family (Felidae) with linear morphometrics and finite element analysis. Our results reveal that relative bite force diminishes slightly with increasing skull size, and that the skulls of the smallest species undergo the least strain during biting. However, larger felids are able to produce greater gapes for a given angle of jaw opening, and they have overall stronger skulls. The two large felids in this study achieved increased cranial strength by increasing skull bone volume relative to surface area. Allometry of skull geometry in large felids reflects a trade-off between the need to increase gape to access larger prey while maintaining the ability to resist unpredictable loading when taking large, struggling prey.

Scaling relationships within the maxillary tooth row of the Felidae, and the absence of the second upper premolar in Lynx

Suggestions that short‐faced members of the Felidae tend to lack the second upper premolar (P2) imply a possible shift in scaling associated with the palate and maxillary tooth row in Lynx, which lacks P2, as compared to felids that retain it. This hypothesis is tested using a scaling model that relates the lengths of the palate, and the upper tooth row and its components, to post‐palatal skull length in the small to moderately large felids Felis catus (domestic cat), L. canadensis (Canada lynx), F. pardalis (ocelot), and F. concolor (cougar). Scaling relationships of both palate and tooth row length to post‐palatal skull length do not differ significantly from isometry in all four species. However, ocelots have a significantly shorter palate and tooth row than lynxes over their overlapping ranges of post‐palatal skull length, suggesting that the absence of P2 is not correlated with the length of the face in these species. CI, P3 and P4 tend to be relatively longer in larger felids; none the less, ocelots have a relatively small P3 and lynxes have a proportionately large P4. Because both lynxes and ocelots have a relatively small gap between CI and P3, the absence of P2 is not correlated with available space within the tooth row in adults. However, lynxes also appear to have a relatively long dP3 that almost obliterates the diastema within the deciduous tooth row. The absence of P2 in Lynx may be an engineering artefact that is associated with a shift in proportions within the deciduous toothrow, resulting in inhibition of the development of P2 and dP2 early in ontogeny. Despite the variable occurrence and polymorphism associated with P2 in the Felidae, this character has systematic value within this clade and is a synapomorphy for Lynx.

THE BREEDING OF SOME LARGER MAMMALS IN NORTHERN RHODESIA

Details are given of a standard manner of recording breeding data of large mammals by game department officers, which is considered a great improvement on previous casual reporting. Information on the breeding in Northern Rhodesia of several ungulates and large Carnivora is summarised, and comparisons made with published data from other territories. It is stressed that much more study is needed, but certain points emerge from consideration of present information. Many species have their young at any time of year, and only a few have a really sharply defined birth season. The wart hog (Phacochoerus aethiopicus) seems markedly seasonal in the south of its range, but not in the northern parts. There is at present no data on the fluctuations in frequency of births among non‐seasonal breeders. In the seasonally breeding species the actual birth months vary somewhat from north to south, and in the wildebeest (Connochaetes taurinus) there may be variation in the calving time due apparently to purely localdifferences of environment. The wild dog (Lycaon pictus) appears to be monoestrus, but data on the larger felids, though incomplete, seems to indicate that young may be born at any time of the year. Limiting factors in the study of breeding in African large mammals are pointed out, but it is suggested that further work on the lines of that carried out in Northern. Rhodesia would be profitable.