Eight Ways Elephant Seals Have Evolved

I took these photos of elephant seals at Piedras Blancas State Marine Reserve in California. Here are some interesting ways that elephant seals have adapted to their harsh environment:

1. As you can guess, their name comes from the large noses of the males. Besides being a way to scare off competing males and attract the ladies, these noses may also help males conserve moisture when they are out of the water. Elephant seals can spend up to 3 months at a time “hauled out” on the beach during breeding season, with their stored blubber their only source of energy and moisture. It is believed that some of the moisture they exhale is captured and reabsorbed by their nose.


2. Another way elephant seals conserve moisture is by producing urine that is more concentrated than many other animals. Yuck, enough said.


3. Elephant seals and monk seals are the only mammals that molt their skin all at once, rather than shedding it continuously in small amounts. This allows them to shut down blood circulation near their skin when they are in the water, helping them to keep warm, conserve energy, and build up that all-important blubber. I was at Piedras Blancas in late July, which is molting season for the males. The tan seal in the photo below has some good molting going on.



4. Elephant seals have really bad sleep apnea. But in their case it is a good thing, allowing them to conserve energy while on the beach without food or water. They can go without breathing for up to 30 minutes while lounging on the beach.


5. Another way that female elephant seals conserve energy is through “delayed implantation” of their embryos. The breeding season includes giving birth, nursing pups, and being impregnated again before going back into the water. But the new embryo will float around in the uterus for 3 or 4 months before attaching to the uterine wall, giving mom a chance to eat and build up her strength before sharing with junior.


6. Elephant seals can dive as deep as 5000 feet. The only mammals that can dive deeper are sperm whales and bottlenose whales. One way they accomplish this is by completely collapsing their lungs before diving, driving out all the air. This prevents nitrogen in the air from dissolving in their blood under high pressure, and coming out when they resurface causing the “bends”.


7. Elephant seals can stay under water for over an hour, then resurface for only a few minutes before diving again. They are able to do this by storing a higher concentration of oxygen in their blood and muscle tissue than other mammals.


8. Elephant seals have been observed eating stones before hauling out of the water for the breeding and molting seasons. When they return to the water, these stones come out the other end. It is believed this helps them fill their stomach while fasting.