Eavesdropping Rodents Listen To Each Other
Fear is a universal language. At least it is for chipmunks and woodchucks. The two animals are completely different rodent species, and while they do not communicate directly with each other, new research has shown that chipmunks and woodchucks will respond to each others’ fear or alarm calls.
This kind of mutual understanding across species is a surprise for researchers because both species are known to be quite solitary. Within their own species the animals do not even live in family groups, so for lone animals to respond to the calls of another species is of interest. Published in the Journal of Mammology, the research explains that while individuals responding to the alarm calls of their own species is a well-documented phenomenon, interspecies understanding is not seen as often.
Led by Lisa Aschemeier of Northwest State Community College, the researchers analyzed chipmunks and woodchucks living in Maine, and recorded their responses to possible dangers. Chipmunks and woodchucks have several common predators including red-tailed hawks, bald eagles and foxes. Aschemeier recorded their response to these threats, in addition to chickadees which pose no threat. She also recorded the alarm calls of crows.
Back in her laboratory the recordings were played over portable speakers, exposing chipmunks and woodchucks to the alarm calls of the opposing species. According to the researchers, woodchucks occasionally tuned in to the chipmunk calls, but more often chipmunks heeded the woodchucks’ warnings. Both chipmunks and woodchucks responded most to the calls of their own species, and neither reacted to the alarm calls of the crow, or to the signals about the non-threatening chickadees.
According to Aschemeier, the larger size of the woodchuck may be why they do not take chipmunk warnings as seriously. The smaller chipmunks are at a greater risk of predation, and are also inclined to signal more. To follow up on this research, Aschemeier hopes to see if any other species, in particular crows, heed chipmunk or woodchuck alarm calls.
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