How smart is a dolphin, or a seal, or an otter for that matter? How can we test for animal intelligence? This week we delve into marine mammal intelligence: their learning abilities, self-awareness and tool use. Here we cover some of the highlights of that work.
Seal & Sea Lion Intelligence
Seal intelligence has not been extensively studied, however one of the most famous cases is the harbor seal, Hoover. In 1971, Hoover was rescued by Maine fishermen as a pup and later moved to the Boston New England Aquarium. But Hoover had a secret – he could talk!
Well OK, “talk” is the wrong word – seals can’t talk, at least not in our language! But Hoover had learned to mimic human speech, right down to the Bostonian accent (trainers believe he might have picked that up from his fishermen rescuers). This feat was discovered in 1971 and Hoover sooner became a celebrity, with people travelling from all over the country to see the “talking” seal. (Check out this video to watch Hoover in action!)
Following this iconic incidence, in 2018 researchers from the University of St Andrews decided to investigate further – could all seals mimic human speech, or was Hoover a unique case? After training three seals to copy various tones, ranging from tones within the normal seal vocal range to ones outwith their normal vocalization range, researchers found that the seals could in fact mimic novel tones. Granted, they did not mimic them perfectly but the similarity was striking given the differences in our physiology. Seals have also been shown to h ave a short-term memory of approximately 18-seconds, demonstrated by a study conducted by the University of Southern Denmark in which capture animals were trained on a specific action, then were trained to respond to the cue “repeat” by repeating the previous action they just performed with no further instruction. The animals all responded correctly, indicating they could remember what they had just done without any further guidance from trainers.
Anyone who’s seen a show at an aquarium, Sea World, or zoos where they give animal performances is familiar with the impressive abilities of the California sea lion. One of the most common marine mammals to see in captivity, this is often because of the trainability of sea lions and their ability to remember and perform specific commands. One captive animal named “Rio” could even solve logic-based equations, such as “If A=B and B=C, C=A”! She was one of the first animals proved to be able to use this type of abstract logic!
Sea lions are extremely coordinated, able to perform strange feats such as balancing a beach ball on their nose (when would they need to do that in the wild?!), and have been known to bob their heads along with music being played. Although these may seem odd for a wild animal, this level of coordination and comprehension make more sense when you think about chasing prey, engaging with conspecifics, and avoiding danger in a 3D environment like the open ocean.
Similar to seals, sea lions have been shown to have excellent short-term memory, but also long-term memory of up to 3-4 months. Studies have shown that sea lions trained to perform tricks in captivity can remember these same tricks even after several months of not performing that specific action or command.
The majority of our research on intelligence in seals and sea lions comes from captive animals, however in 2015 a mass mortality event occurred in California sea lions, providing a unique opportunity to study the brains of this incredible mammal. Researchers from Vanderbilt University found that sea lions have a very large brain, with large sensory cortexes that correspond to their whisker region. (Similar large sensory areas have been found in mice and other rodents that regularly use whiskers as a way to detect food and obstacles.) In fact, the amount of brain-space taken up by whisker-sensing in the sea lions was equivalent to the amount of OUR brains used for finger sensation!