Birth of world's rarest chimpanzee at Chester Zoo brings hope. This is what happened

Although both chimps and Orangutans have the ability to learn sign language, use tools, what sets them apart is their ability to understand the reason behind their actions. Orangutans are so smart that they share 97 per cent of its DNA with humans. They can be trained to use hammers and nails. Sadly, they are critically endangered due to habitat loss.

Source: AZ Animals

Bottlenose dolphins are on number two in the list of world's smartest animals. Bottlenose dolphins are said to have the largest brain size among other dolphins. They are also the only dolphin without fused cervical vertebrae that they use to make human-like nodding motions with their heads.

Chimpanzees are said to share 98 per cent of their DNA with humans. Chimpanzees also have the ability to manipulate others to get certain tasks done. Adult members in the chimp family teach their young sign language.

Elephants are one of the smartest animals in the world with the longest memory. They are capable of treating themselves by eating certain plants and leaves to cure themselves and even induce labor.

The African grey parrot is estimated to be as smart as a five-year-old human. These humans can learn human speech/ language but can also learn up to 100 words. They also recognise shapes and colors. They can also be taught relationships between bigger and smaller, over and under.

Octopus can also understand solving mazes, and problem-solving experiments making it the only invertebrate animal to be on the list of world's most intelligent animals.

Pigs have comparatively much higher IQ levels than dogs. They understand the concept of reflection and all when they are only six weeks old. They have as many as 20 different sounds that they use to communicate. They also respond to emotions and show empathy.

Possessing the largest brain of all avian species, Crows are also highly intelligent animals. They have also been used as messengers like pigeon. Crows also have impressive memory and learn speech.

Pigeons have a complex sense of self-awareness . They can recognise their own reflection and also have the ability to recognise specific people and places. Pigeons can also identify the letters of the English alphabet and can also recognise two people in picture.