Nature: All things bright and beautiful

Scientists are arguing that dolphins are so clever they should be treated like humans. But why stop there? Simon Usborne salutes the smartest species

An extraordinary council of marine mammals was clicking late into last night to consider the future of cetacean species after human scientists proposed a declaration of rights for some of the world's smartest animals...

...Well, if they're that clever, they would be, right? A group of biologists and philosophers said at a conference in Vancouver this week that dolphins and whales were so smart they deserved to be treated as "non-human persons". But why stop there? Nature is overrun with over-achievers who threaten the supremacy "human persons" earned mainly by killing things and inventing calculators. Let's take a moment to marvel at their staggering feats and brilliant brainpower.

1. Elephants

They have good memories but have also been observed using tools and showing empathy, evidence of a higher form of intelligence.

2. Pigeons

These pestilent crumb munchers can identify themselves in mirrors and distinguish between objects.

3. Crows

Bird-brained but brilliant crows can place nuts in streets to be cracked under cars, retrieving the spoils after the traffic lights have changed.

4. Horses

Clever Hans wowed early 20th-century audiences with feats of arithmetic. A commission later found the German horse, while clever, was no genius.

5. Dolphins

Bottlenoses off Brazil drive fish towards fishermen and then swim away, nabbing lunch as they go.

6. Chimps

Ayumu makes his scientist handlers look stupid. When shown numbers on a screen for half a second, the Japanese chimp can then trace their position in perfect sequence.

7. Pigs

Sows in Essex have learned to "borrow" the electronic collars of other pigs to gain cheeky seconds from their computerised feeding system.

8. Dogs

Uggie, The Artist star, is a master of tricks but can't out-smart Chaser, a collie from South Carolina, who has learnt the names of 1,000 objects.

9. Rats

They can navigate mazes and trip levers for food but scientists in Los Angeles showed in 2006 that rats can also distinguish cause from coincidence.

10. Octopuses

Paul, the octopus who predicted results during the 2010 World Cup, wasn't psychic but his kind can open jars or valves to their tanks (one flooded a Santa Monica aquarium).