Nibbles, the Wayward Elephant Seal
Why is this animal harassing harbor seals, dogs and humans?
Nibbles, a juvenile elephant seal has been attacking other inhabitants at the mouth of the Russian River. Some possible reasons are based in his species' natural history
A young northern elephant seal (Mirounga angustirostris), nicknamed Nibbles, is causing a stir in California. He has been called a ‘rogue’ after attacking a dog, killing harbor seals (Phoca vitulina), harassing kayakers and ‘growling’ at a surfer. But his behavior, while possibly misdirected, may not be completely abnormal.
Elephant seal bulls compete for territory on rookeries during the breeding season. At 2,000 pounds Nibbles is probably 4 or 5 years old, which is just at the edge of maturity. But he will not reach prime breeding condition until he is 8 or 9 years old. One possible explanation for his behavior is that he is practicing for the time when he is ready to compete for territory.
Suggestions that he is alone because he is not big enough to compete for females doesn’t make sense since northern elephant seal breeding season is over. The elephant seal rookeries on the California coast are filled right now with juveniles and will continue to be until late May. The bulls are already in the open ocean feeding, after having fasted for much of the winter while guarding their territories.
In spring, young elephant seals haul out to molt. This process involves shedding the fur and upper layers of skin, during which time the animals rest on the beach without eating. Once the molt is complete the juveniles go back into the water, often spending time learning to fight with each other before leaving the haulout area to feed in the open ocean.
In this case, there are no other elephant seals around, so Nibbles may be going after whatever is nearby-dogs, surfers, kayakers and harbor seals. In an elephant seal colony other animals of the same age would fight back. Same age conspecifics (animals of the same species) are not usually injured in these mock fights. Someone gives up and swims off before blood is shed. Smaller, younger animals just get out of the way. .Dogs and harbor seals don’t react in the way the younger elephant seals would, which may explain Nibbles’ reaction to them. The humans moved away, behaving like an elephant seal would and they were then left alone. The person whose dog was attacked was able to get the massive animal to back down, a testament to the general docility of the species.
Animals that have left the rookery travel alone to the feeding grounds, so his being by himself is also not unusual, but his interaction with the other inhabitants of the area is. As is often the case when animals behave differently, it likely that no one will ever know why Nibbles is doing what he is doing. But it is interesting to watch and fun to speculate on.
