Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Why orcas go through menopause

orca

Image of an orca and her calf from Wikimedia Commons

Orcas are one of only three species of mammals that go through menopause, including humans of course. A new study published in Current Biology may have discovered why this happens in killer whales.

Examination of 43 years worth of data collected by the Center for Whale Research and Fisheries and Oceans Canada, revealed a remarkable finding about the costs of reproduction in orcas. Older mothers tend to spend more time taking care of the family, so to speak, by making sure her offspring know where or when to find food. While this cooperative foraging behavior helps improve survival of the mother’s family, further offspring from the mother are 1.7 times more likely to die than her daughter’s offspring. This reproductive competition (or conflict) is thought to be a reason why the whales (and perhaps humans) evolved to go through menopause.

Source:

DP Croft, RA Johnston, S Ellis, S Nattrass, DW Franks, LJN Brent, S Mazzi, KC Balcomb, JKB Ford, MA Cant. Reproductive Conflict and the Evolution of Menopause in Killer. Current Biology. 27: 1-7, 2017. DOI: 10.1016/j.cub.2016.12.015

Categories: Comparative Physiology

Tags: , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s