Evolution in coyotes (Canis latrans) in response to the megafaunal extinctions

Abstract

Living coyotes modify their behavior in the presence of larger carnivores, such as wolves. However, little is known about the effects of competitor presence or absence on morphological change in coyotes or wolves over long periods of time. We examined the evolution of coyotes and wolves through time from the late Pleistocene, during which many large carnivorous species coexisted as predators and competitors, to the Recent; this allowed us to investigate evolutionary changes in these species in response to climate change and megafaunal extinctions at the end of the Pleistocene. We measured postcranial skeletal morphologies of wolves (Canis lupus) and coyotes (C. latrans) from Pleistocene-aged tar deposits, as well as early, mid, and recent Holocene populations of both. We found few morphological differences between Pleistocene and Holocene wolf populations. Conversely, we found many differences in coyotes: Pleistocene coyotes were larger and more robust than Holocene populations. However, within 1,000 y of the megafaunal extinctions, coyotes are morphologically indistinguishable from modern populations. We cannot attribute these differences directly to climate change because modern coyotes do not follow Bergmann's rule, which states body size increases with decreasing temperature. Instead, we suggest that Pleistocene coyotes may have been larger and more robust in response to larger competitors and a larger-bodied prey base. Although we cannot separate competition from predator-prey interactions, this study indicates that the effects of biotic interactions can be detected in the fossil record.Pleistocene extinctions | Canidae | Rancho La Brea

Taxonomic Implications of Morphological and Genetic Differences in Northeastern Coyotes (Coywolves) (<em>Canis latrans</em> × <em>C. lycaon</em>), Western Coyotes (<em>C. latrans</em>), and Eastern Wolves (<em>C. lycaon</em> or <em>C. lupus lycaon</em>)

“…These weights are similar to the estimated mass of Ice age Coyotes during the Pleistocene era, believed to be "super-sized" compared to modern Coyotes (Meachen and Samuels 2012). Chambers (2010) asserted that previous researchers (e.g., Bossert 1969, 1975) measuring canid morphometics grouped northeastern Coyotes with other populations of Coyotes and hence they should continue to be called Coyotes.…”

Adaptive, convergent origins of the pygmy phenotype in African rainforest hunter-gatherers

“…Such a scenario may be perceived as unlikely, because it would require major, convergent body size reductions over only several thousand years. However, recent nonhuman studies have shown that body size may undergo substantial evolutionary change in relatively short timeframes (56,57). The case of rainforest hunter-gatherers could be a similar human example of this phenomenon.…”

Cranial morphometrics of the dire wolf, Canis dirus, at Rancho La Brea: temporal variability and its links to nutrient stress and climate

“…Carnivore community composition can also impact carnivore morphology; the presence of other carnivores can drive dental character displacement in a range of species (Dayan, 1992;Dayan and Simberloff, 1998). Recent work by Meachen and Samuels (2012) documents this effect at La Brea, finding stasis in C. lupus but change in C. latrans across the Pleistocene/Holocene transition. Detailed geometric morphometric analysis of shape and size change across the carnivore guild at La Brea has yet to be attempted.…”