Solving a tricky puzzle can be one of life's little pleasures – just ask raccoons. Researchers recently discovered that these mammals solve puzzles for the fun of it.
The raccoons were presented with a clear plastic box with a marshmallow inside. The box could be opened in multiple ways, ranging from easy (e.g. a slide latch) to difficult (e.g. a turn knob).
Even once they’d recovered their sweet treat, the raccoons often continued opening different mechanisms – what the researchers call ‘information foraging’.
In other words, they seemed to be driven by curiosity – a trait that could help explain their ability to adapt to urban environments (and cause mischief, like the raccoon that ransacked a Virginia liquor store in 2025).
Chimpanzees are also keen puzzlers. In 2013, six chimps at Whipsnade Zoo were tasked with prodding objects through a maze of plumbing pipes using sticks.
Sometimes the retrievable objects were dice, sometimes they were edible treats (Brazil nuts) – and, like the raccoons, the chimps were still keen to solve the puzzle without the food reward, leading the researchers to suggest that these animals get a sense of satisfaction from completing complex brain games.
Being able to think flexibly and solve problems is a key indicator of animal intelligence.
Asian elephants at Salakpra Wildlife Sanctuary in Thailand have shown that they can open puzzle boxes with their trunks to access food (in this case, pulling chains or moving doors to find jackfruit).
Underwater, meanwhile, octopuses are the ruling puzzle champions.
A 2016 study presented octopuses with small L-shaped containers, which they learnt to open to find a piece of shrimp. The container was then placed behind a plastic separator with a hole in it.
Using their dexterous arms, the octopuses were able to manipulate the awkwardly shaped container and pull it through the hole.
When it comes to the ultimate puzzle-solving prowess, though, New Caledonian crows may rule the roost.
These birds have been observed using tools in captivity and the wild, bending wire or twigs into hooks to retrieve food. They can even make tools out of multiple parts.
In 2018, researchers gave crows a puzzle box containing food that could only be retrieved by poking a stick through a narrow gap.
The eight crows were provided with sticks that were too short to reach the food, but that could be combined to create ‘compound tools’. Half of the birds spontaneously worked this out, with one bird creating a pole out of four individual pieces.
But it gets even more impressive: crows can solve puzzles with multiple stages.
In the 2014 BBC series Inside the Animal Mind, a crow was filmed solving an eight-step conundrum that it hadn’t encountered in full before.
It used a small stick to obtain three stones, dropped them into a weighted device to access a longer stick, and then used that to retrieve a food reward.
Maybe being ‘bird-brained’ is actually a compliment.
This article is an answer to the question (asked by Rahul Patil, via email) 'What animals are best at puzzles?'
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