Our Elephant Seal Rookery
Elephant Seals. Photo taken by Naturalist Laas with a zoom lens and heavily cropped.
  • July 30, 2019

The Race Rocks Lighthouse and Ecological Reserve is a spot we frequently visit on our Whale Watching Tours. In addition to being plentiful with marine life it is the most northern elephant seal rookery. It has only been a rookery for the last 10 years and is slowly growing. For the first time last year, 3 elephant seal pups were born, in previous years there has never been more than one or two. Elephant seal pup mortality occurs in every rookery, unfortunately it did occur at this rookery last year. The third pup was attacked by one of the other mothers and her injuries were eventually fatal. At this point I was in contact with marine mammal rescue but we decided since the pup was still with her mother and attempting to nurse, it was best to leave her with mom.

The first two pups did very well, they gained weight at a steady pace and eventually learned how to swim and hunt.  An elephant seal pup usually nurses for about 3-5 weeks depending on the mother. Elephant seal pups gain about 10 pounds a day and their mother will lose up to 45% of her body weight. It is common for male pups to be ‘milk stealers’ and that was the case after the male pups mother left this year, he continued to nurse with the mother who had lost her pup. He was quite large by the time he was weaned and so was the female pup but she didn’t nurse for as long. The difference between the two was at least 100 pounds!

Elephant Seals
Elephant Seals. Photo taken by Naturalist Laas with a zoom lens and heavily cropped.

After the mothers leave, the pups will play and learn how to swim, I could always find them in the water at sunrise and sunset splashing around. It is typical for a group of pups born in the same year to leave together when the time comes. This year was different, after the female pup left, the male pup stayed around for at least another 4 weeks. It is unusual for a pup to stay that long but I knew he would leave when he was ready and got hungry enough. I watched these pups being born and watched them grow up, I named them Nemo and Dory. You get very attached to them and worry a bit when they decide to go out on their own.

The relationship between a pup and its mother is interesting, as soon as the pup is weaned and even if the mother comes back, they don’t really acknowledge each other. Dory’s mother did come back a few weeks after she left and it looked like they didn’t even know each other. Elephant seals do tend to stick to their own age groups, even the time of year they are moulting, depends on gender and age. The older females and young males are moulting in April and May, the older males are molting in June and July. Why these animals chose Race Rocks as a sort of home base through the years, I’m not entirely sure. They tend to be found on sandy beaches because covering themselves in sand helps protect them from getting sunburned. Race Rocks is just rocks and grass, it doesn’t provide much sun protection, but there are occasionally some muddy areas they like to roll around in. The boat ramp also helps, it makes a very easy access point for them to come in and out of the water. The only humans they have to deal with are the lighthouse keeper which is usually me. I give them their space and they don’t mind seeing me walk around the island doing my chores.

Elephant Seals
Photo taken by Naturalist Laas with a zoom lens and heavily cropped.

One thing I am hoping is done in the future is tagging. Dory’s mother was tagged and it was great because I contacted the research centre that tagged her and was able to find out how old she was and where she was born. I also found out who Dory’s grandmother was and when she was born, it was very interesting and I wish we could’ve tagged Dory. I love finding out the history of each elephant that comes to Race Rocks with a tag on its tail, it gives us a lot of information about its history, age, gender, migration, and haul out spots. This gives us information about the northern elephant seal population in general. At the moment most of the northern elephant seal rookeries are in California and since this is a fairly new rookery I understand we don’t currently tag but in the future it is something to think about as this rookery grows. Here’s hoping for at least 3 healthy baby elephants in January.

Blog written by Naturalist Laas, Lighthouse Keeper at Race Rocks.

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