Be an otter for a day

The forecast for Bloomington this week is warm and sunny weather every day. It seems like the perfect time to unpack your swim suit from spring break, or worse, last summer.

Outdoor pools are not opening for another few weeks, but there are still plenty of outdoor water holes around town for you to enjoy your favorite water activities.

You might think your mammalian body is meant for terrestrial habitats, but think again, landlubber. Mammals everywhere love aquatic habitats, and luckily your body can handle the swim.

Mammals evolved on land from reptiles that had already adapted to life on land. When animals moved out of the water, they acquired many adaptations for life on land, including improved means of support, locomotion, respiration, excretion and reproduction. Even though mammals evolved on land, many returned to aquatic habitats partially or even completely.

In a 2006 Science article, scientists revealed the earliest known mammal with specific adaptations for swimming. According to the article, Castorocauda lutrasimilis lived at least 164 million years ago, possessed skeletal and tissue adaptations for swimming, and dental features beneficial for aquatic feeding.

They looked a lot like modern-day beavers with broad and scaly tails, though beavers did not appear for at least another 100 million years. The article also compares C. lustrasimilis to the platypus, the semi-aquatic, egg-laying, poisonous mammal of Australia.

The mammalian order Cetacea contains the mammals that completely returned to aquatic habitats. It includes whales, dolphins and porpoises. Contrary to what you might think, these animals did not evolve from fish but from terrestrial mammals. Their forelimbs became fins, and they still require air for breathing. Hippopotami are their closest living relatives.

While humans have not evolved to live their lives in water, we still enjoy the occasional dip. In fact, humans can swim at around 2.2 meters per second, which ends up being about five miles an hour. Killer whales have us beat at around 30 miles an hour.

Barely three miles north of the center of campus is the Griffy Lake Nature Preserve, where you can rent canoes, kayaks and rowboats and go fishing or hiking, but you may not go swimming.

Southeast of town is Lake Monroe, Indiana’s largest lake. There you can boat, fish, water ski and swim. Daredevils and lawbreakers might try one of the many limestone quarries that surround town, but beware of police officers, dangerous cliffs and creepy aquatic creatures.

The water in these places is only heated by the sun, so it will probably still be cold from the winter. Wherever you choose to go, take a chance and pretend to be an otter for a day.


E-mail: kslabosk@indiana.edu