From phys.org:

In many parts of the world, there is an imbalance in the food chain.

Without top predators such as wolves and grizzly bears, smaller meat-eating animals like coyotes and foxes or grazers such as deer and elk can balloon in population, unchecked. This can initiate more deer-vehicle collisions, scavenging by urban coyotes and other unnatural human-animal interactions.

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