A sea otter floating on its back in the waters of California’s Monterey Bay grabs a shelled animal and smacks it against a rock resting on its chest. This will help the otter break open the prey and access their food.
This behaviour, captured in footage by researcher Chris Law, is not commonly observed in many animals. It’s a unique ability that allows the sea otter to obtain food without damaging its teeth. A recent study, which will be published in the journal Science on Friday, provides valuable insights into the threatened species’ tactics.
Using tools can help them eat proper food.
Researchers discovered that when the sea otters’ favourite food, like abalone and sea urchins, they use tools that are able to eat larger prey like crabs and clams. This helps them avoid dental injuries. Interestingly, most of the otters that do this are females, as per the study.
A postdoctoral researcher at the University of Texas at Austin says that the tools allow them to overcome their smaller size and weaker bite ability, ensuring they get enough calories to meet their needs.
The study focuses on sea otters in Monterey Bay, which is in California on the central coast. Where the southern sea otter population lives. These otters used to occupy waters from Alaska to Baja California. Until they were almost wiped out because of the fur trade near extinction.
The US Fish and Wildlife Service considered bringing sea otters back to the west coast. Due to conservation efforts in the 1970s, their population has slowly increased, and today there are around 3,000 sea otters in California.
In central California, sea otters love to feast on sea urchins and abalone, which are usually easier for them to crack open, but those species are declining, the law said. Because of that, they will more often seek out crabs, clams, and mussels, as well as marine snails.
Study says the hard shells of the snails can damage the otter’s teeth if they try to open them with their mouths.
In central California, sea otters love to eat sea urchins and abalone, which are usually easier for them to open. Unfortunately, these prey species are decreasing in number.
As a result, otters are starting to look for other food sources like crabs, clams, mussels, and marine snails. However, the study highlights that the otters need to be careful with the hard shells of the snails because they can harm their teeth if they try to open them with their mouths.
According to the law, the decline in their favourite prey is due to fishing and habitat destruction, so they have to switch to alternative prey. Law said. They found that this behaviour allows them to switch to those prey.
Research and observation
The researchers and volunteers closely followed 196 otters by outfitting them with radio tags.
Law, an evolutionary biologist who completed the research as part of his dissertation at the University of California at Santa Cruz, mentioned that sea otters primarily use rocks as hammers. However, they can also use shells, trash, and even boats or docks on occasion.
The female sea otters who use tools are capable of consuming prey that is up to 35% harder compared to the males who also use tools. While it is not clear whether tool use is increasing among otters, the behaviour is beneficial for the animal.
If there aren’t any urchins or abalone available for them to eat, and they are faced with other prey types they can’t open, they can’t survive.
