Examples of logical intelligence and abilities across different groups of animals
Can animals solve problems?
For more than a century, psychologists have studied logical intelligence in other species. Edward Thorndike was one of the first, with his experiments to see whether cats could escape from a simple puzzle-box.
Escaping from a box is an example of logical problem-solving: overcoming an obstacle in order to achieve a goal. Modern researchers use similar tests, as well as observing animals solving problems in the wild.
Logical intelligence is often linked to tool use. As recently as the 1960s, people thought that tools were only used by humans, but this is not the case. Crows make hooks out of twigs, octopuses carry armor, and even crocodiles have been seen setting traps for unsuspecting birds.
Tool use in mammals
Primates are adept at using tools to solve problems. Chimps use sticks to fish for insects, and make pointed spears to hunt for small animals. Gorillas use logs to test the depth of a river before trying to walk across.
Primates are not the only mammalian tool-users. Dolphins in Australia put sponges on their noses to protect their faces while foraging for food. Mothers teach this skill to calves, making sure the knowledge passes through generations.
This is an example of cultural learning. At some point in the past, a dolphin learned to use a sponge, then shared the knowledge with the rest of the group. It has only ever been observed in one pod, which suggests these dolphins want to keep the knowledge to themselves.
Tool use has also been observed in other mammals, including bears, honey badgers, pigs and otters.
Tool use in birds
Alongside mammals, the animal kingdom’s most prolific tool-users are birds. The New Caledonian crow is a striking example, which outperforms chimps in most logical tests.
These birds craft tools out of leaves and sticks, carefully fashioning them into useful shapes. They invent new tools to combat novel problems, like a hook-shaped tool to reach an insect nest hidden down an awkward bend.
In laboratory tests, crows have also demonstrated meta-tool use: using one tool, to obtain a second tool, which then helps them to reach some food. Problem solving using two different tools in two different steps suggests a high capacity for logical reasoning, which few other species are capable of.
Tool use has also been observed in other birds, including parrots, herons, finches and Egyptian vultures.
Fish and cephalopods
In recent years, the logical intelligence of octopuses has gained a lot of attention. Wild individuals have been seen collecting coconut shells, and wielding them like shields, or pieces of armor.
At an aquarium in Germany, Otto the octopus learned to throw stones at the sides of his tank, in an effort to break the glass. He also sprayed water to short-circuit a lamp, probably because he did not like the glare.
Some species of fish can also use tools, like the wrasses who use rocks to open clams. Stingrays adjust the shape of their bodies to redirect currents, using the flow of water to extract hard-to-reach pieces of food.
Insects and reptiles
Tool use has rarely been observed in reptiles, which do not excel when it comes to logical intelligence. But in 2007, one notable exception was observed in India.
A crocodile will hold a pile of twigs at the end of its nose, then lie motionless beneath the water. When a bird tries to collect the sticks, the crocodile attacks. The crocodiles only use this technique during nesting season, when birds are on the lookout for sticks.
Tool use is common in insects. Ants use stones to block the tunnels of rival colonies, while bumblebees in a laboratory test learned to roll a ball to a specific location in order to receive a treat.
Instinct vs. insight
Some scientists argue that tool use in other species is not a true indication of logical intelligence. The debate comes down to two interpretations: instinct versus insight.
Instinctive tool use is an automatic behavior that a species evolves over millions of years. Crocodiles, for example, do not actively decide to set a trap for birds. This is an innate behavior, which they perform automatically. It does not involve any creative, logical thought.
Insightful tool use is when an animal encounters a brand new problem and comes up with a tool to overcome it. Birds, primates, and octopuses have demonstrated insightful tool use. Their creativity and flexibility is a sign of logical intelligence.
Animal numeracy
Alongside problem solving and tool use, another sign of logical intelligence is the ability to handle numbers.
Mathematical ability is rare in other species, probably because the evolutionary benefits are limited. It is unclear why humans evolved such impressive numeracy skills, but it may have helped them keep track of resources.
Some shoaling fish can count and compare numbers. When they see two shoals, they will usually join the larger one; there is an evolutionary benefit to comparing the numbers, and joining a stronger group.
In captivity, a parrot named Alex was taught to count, and to perform some basic sums. This suggests that his brain was capable of math, although he never would have evolved these skills in the wild.
Differences in ability
A subject of debate, in academic circles, is whether or not two individuals within a single species can be born with different levels of intelligence.
For example, while Alex the parrot learned basic math, other parrots of the same species have shown no signs of learning. Some chimps use sticks to fish for termites, while others never learn this skill, even with extensive training.
It is hard to know whether these differences are genetic, or the result of environmental differences. Some studies suggest that cognitive skills are heritable in chimps, but the research is inconclusive. In the coming years, this topic will demand further study.
