I’m teaching an Animal Behavior course this semester. The lectures are 80 minutes long and exactly during the sleepiest time of the afternoon; I enjoy the challenge of getting a reaction from the students under these circumstances. Videos of baby animals in peril always get attention (some good ones: marine iguana, barnacle goose, water buffalo), but they’re so reliable it almost feels like cheating.
My students have actually broken into applause during lecture three times so far. One of these will not be discussed in detail (it involved the recitation of poetry), but the other two were in response to two quite different animal accomplishments, which I thought I would share.
The whelk that survived
Mollusc shells are a physical record of the experiences of the animals that make and wear them. Shell color and shape can tell you about the lifestyle of the animal, and damage to the shell can tell you how the animal eventually died. But not all damage is fatal. Sometimes a predator—generally a crab—tries to break the shell, and manages to break some pieces off, but then finds it too hard and gives up. The surviving but damaged mollusc continues to grow its shell, which retains a scar as evidence of the animal’s close call with crunching death.
This whelk had a seriously dangerous encounter with a crab, as you can see from the jagged edge of the old break. Yet, as evidenced by the newly-grown shell past the scar, it survived to whelk another day.
Birds can fly incredible distances on their annual migration. The Arctic Tern is the champion, flying clear from one pole to the other twice a year. The Arctic Tern has a critical advantage: since it eats fish, it can refuel even while migrating over the ocean. The Bar-tailed Godwit, another long-distance migrant, has no such advantage: it is a shorebird who catches invertebrates by probing its bill into wet sand. This is not something you can do while in flight over the Pacific, no matter how long your bill is.
It is therefore not surprising that godwits tagged with locators made stops on their way between Northern Russia or Alaska and New Zealand, pausing off on the shores of the Yellow Sea in China, or the beaches of Pacific islands, to rest and eat.
That is—most of the godwits did. But one, a female dubbed “E7,” didn’t need a break. She flew the 7,145 miles from Alaska to New Zealand nonstop. It took her 8.1 days.
Battley PF, et al. 2012. Contrasting extreme long-distance migration patterns in bar-tailed godwits Limosa lapponica. Journal of Avian Biology 43:21-32.
Dietl GP, Hendricks JR. 2006. Crab scars reveal survival advantage of left-handed snails. Biology Letters 2:439-442.
*Photos obtained from Flickr and used via Creative Commons. Many thanks to these photographers for using Creative Commons!