Today's Amazing Nature column is going to be about some mammals in the sea and some that are only sometimes in the sea, but depend on it for part of their diet.
While one could say the same about humans — that we depend on the ocean for part of our diet — the three animals I want to write about are all mustelids; small carnivores in the weasel family. However, only one of them is a true weasel, the other two are otters. Confused? The weasel family mustelids includes about 60 species in eight subfamilies which include weasels, badgers, otters, ferrets, martens, mink and wolverines.
Native to Kodiak is the land or river otter (two names for the same beast), and the ermine, which is a weasel. In addition, the ocean around Kodiak is home to the now once again common sea otter, which shares the same subfamily with the land otter. They also share some of the same food sources. As I have often mentioned, sea otters are not very selective in what they eat and can be seen munching on many species of shellfish, crabs, sea urchins, worms, and if they can catch them, also fish. Land otters specialize in fish, whether they are from rivers, lakes or directly out of the ocean.
Earlier this summer I was on board a skiff on my way to one of the beaches in Shuyak when we spotted an animal swimming near the shore. As we gave it a berth and passed by the animal gave us an irritated look, but continued undeterred as it was swimming around a rocky outcropping. This was not a sea otter, it was a land otter in search of food in the ocean. Land otters have a somewhat flattened head, are generally smaller and have a long tail that trails behind when they are swimming. They do love fish and I have seen them hunt fresh water fish in Auke Lake in Juneau, eat a flounder on the beach in Cordova, and steal salmon smolt out of a trap at Spiridon Lake on Kodiak Island. According to Wikipedia one of their main prey are sculpins.
What really made me want to write about these weasels, however, was a scene I witnessed just last week in Anton Larsen Bay. I was on board with a group of bird and wildlife watchers and photographers when we came across two sea otters, one of which was hauled out on a floating log. Since it is not common to see sea otters out of the water and these two otters were displaying a lot of interaction, which is cute to watch, we observed them for a while. Suddenly, the captain pointed at something in the water and I heard someone ask "what is that?" It took me a while before I saw what the excitement was about. There was a small creature swimming through the water. My first thought was muskrat, but that was not it. What we were seeing, was a short-tailed weasel, also called an ermine.
America has a short tailed, a long tailed, and a least weasel, but according to my internet sources, Kodiak Island only has the short-tailed weasel. Interestingly, while in all my years of living on Kodiak I usually only saw a weasel about once a year, this week alone I had seen three of them in different places and at different times. Perhaps this is a good year for local weasel populations? Weasels like to eat small rodents like shrews, mice, moles and rats, but will also take rabbits, and if there are not enough of those prey animals around, they will go for insects, worms, frogs and fish. I always marvel at the metabolism of sea otters, which can eat 30% of their body weight daily. The weasel beats that: it consumes 40% of its body weight, that is ten times as much as a human eats by percentage.
However, as we were watching from the boat, this weasel was not eating; it was spending energy. It was in the middle of the Bay, miles away from either shore, swimming strongly with what looked like a front paw freestyle stroke. It was the most amazing sight! Though apparently short tailed weasels can be bigger in some parts of the world, this one was no more than 10 inches in body length and about half as much again for a wet and soggy tail. I wondered how this small animal had brought up the courage to take on such a long swim and what motivated it to do so. How could it even know where the other shore was, or for that matter, if there was another shore? One thing is for sure, if it was there by its own free will, it was a lot braver and more certain of its swimming stamina than I would ever be, and I consider myself a fairly good swimmer.
Because the creature was so small, we soon lost sight of it and took the boat towards shore where our guests had spotted an eagle in a tree, posing for nice pictures. After a few minutes the eagle took flight and the camera's clicked excitedly. Then, we watched as the eagle swooped down on the water, missing on the first attempt, then swooped down again, only to carry a small furry creature in its talons to the beach. There, the eagle turned its rear end toward us and we could only guess at the fate of our small, swimming hero as the sharp beak of the eagle went to work. Some days you eat the rabbit, some days the eagle eats you. It's an amazing, but sometimes cruel world out there.