Capuchin monkeys have been observed abducting baby howler monkeys in the wild.
Why it is true
Biologists documented five male capuchin monkeys carrying at least eleven different infant howler monkeys, a behavior never before seen in wild primates. The study offers the first known documentation of a cultural tradition in which animals repeatedly abduct and carry infants of another species, without any clear benefit to themselves.
Source: Max Planck Institute
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