The impact of climate change over the last 37 million years on vegetation and habitats affected the predatory behaviour of canids (carnivores including wolves and foxes) in North America, reports a paper published in Nature Communications. The research, based on a 37 million-year-old fossil record, shows that the elbows of foxes and wolves changed in response to increasingly open habitats to allow for pursuit over both short and long distances.
During the late Cenzoic, the Earth’s climate underwent a profound change from warmer and more humid climates to the cooler, increasingly modern climates present today. Fossils of plants from this time show a corresponding change in vegetation structure, with increasing levels of grasslands towards the end of the Oligocene (27 to 23 million years ago). The effects of this change on large carnivores are less well known.
Borja Figueirido and colleagues examined the well-documented fossil record of North American canids to see if their predatory behaviour was influenced by environmental change during the Cenzoic. They tested for direct association between predatory behaviour and environmental events rather than an ‘arms race’ model of evolution between predator and prey.
They find that canids, originally ambush predators, demonstrated a gradual change in the shape and function of their elbow joints which eventually meant that their hunting involved pursuit. Pounce pursuit predators, who sprint after smaller prey, began to appear approximately 7 million years ago. True pursuit and endurance canids such as wolves, which chase prey over long distances, appeared later with the cooler and more arid conditions of the Pleistocene (2 million years ago).