Which Animal Has the Biggest Brain on Earth?

This article will answer the question “Which animal has the biggest brain on earth?” and it will also highlight features of the same animal. The article will compare the human brain with the animal and highlight some differences. The article will answer some frequently asked questions in the end.

Which Animal Has the Biggest Brain on Earth?

The sperm whale is said to have the biggest brain as compared to any other animal. The brain of a sperm whale weighs upto 20 pounds or around 7 to 9 kilograms. However, having a big brain does not mean that the mammal is smarter than those who have smaller brains. 

But, as mammals evolved, many groups of animals ranging from primates to Carnivora, have shown a spurt in their brain size. This means that bigger brains must provide some evolutionary benefits to the organism. 

Whales and dolphins belong to the same species. Whales have approximately 37.2 × 109 neurons, which is almost two times as many as humans, and 127 × 109 glial cells.

Dolphins belong to the Cetaceans species. There are two types of cetaceans namely odontocetes, who are toothed whales and mysticetes, which are baleen whales (Gingerich et al.1983). Cetaceans went through major transformations in their bodily forms during secondary adaptation to water. This resulted in them having highly encephalized as well as huger brains as compared to other terrestrial mammals (Oelschläger and Oelschläger, 2002). 

Previously it was believed that organisms that have large brains are more intelligent. Thus, it is no surprise that dolphins, who possess larger brains as well as display complex behaviour are believed to be very intelligent. 

Research has found that there are 12.8 billion neurons in the neocortical neurons in the Minke whale. This means that the minke whale has 13 times more neurons as compared to rhesus monkeys and 500 times more than rats! However, the minke whale only possessed about 2/3rd of its neurons compared to the human neocortex. 

These findings are interesting because it highlights that Minke whales, who are a species of dolphin, are shown to have more neocortical neurons as compared to any other mammal studied to date. 

However, since the neuron density in long-finned pilot whales is found to be lower than the neuron density in humans, the large number of neurons in dolphins can be attributed to their bigger brains. 

Whale and Dolphin’s Intelligence

When we discuss cetacean intelligence, it includes the discussion of cognitive abilities of the cetacea of mammals. Cetacean mammals include whales, porpoises, and dolphins. 

Brain size has been considered to be a predictor of intelligence in animals. However, newer studies have shown that there are several factors influencing intelligence as new evidence of birds’ intelligence has come up. Thus, we now know that a bigger brain does not necessarily equal more intelligence. 

The brain is used for the maintenance of bodily functions, and thus, the greater the ratio of brain to body mass, the more mass is available for the brain to perform complex cognitive tasks. 

It has been found that dolphins have a faster brainstem transmission time as compared to humans. The speed of brainstem transmission in dolphins is equivalent to that of rats. 

Whales have a greater dependence on sound processing, and this is evident in the structure of their brain. Interestingly, the neural areas that are responsible for visual imaging are equivalent to 1/10th of the human brain. However, the neural area devoted to acoustical imaging is around 10 times as large as compared to the human brain. 

Some research has also highlighted that dolphins are one of the fewer animals that understand concepts of numerical continuity, and are able to distinguish between different numbers. 

Numerous research focused on observing the abilities of animals to learn set formation have found that dolphins have nearly the same level of intelligence as elephants. In a survey done in 1983, it was found that dolphins rank highly in the learning of “set formation”, but they’re not as good as other animals. 

Whales engage in play behaviour that is complex including the production of stable underwater toroidal air-core vortex rings. These are also called “bubble rings”. Dolphins are also found to play by riding in the waves, much like human “body-surfing”. 

Cetaceans also have self-awareness. Self-awareness is described as an advanced process similar to meta-cognition (thinking about thinking) which is typical in humans. Scientific research has suggested that bottlenose dolphins apart from elephants and great apes possess the skill of self-awareness. 

The self-awareness test used for assessing it in animals is the mirror test developed by Gordon Gallup (1970) and is the most widely used test. Here, a temporary dye is placed on the animal’s body and the animal is placed in front of a mirror. The test assesses whether the animal is able to identify itself. 

Marten and Psarakos tested the self-awareness of dolphins in 1995. They showed real footage of the dolphins through television of dolphins identifying themselves in the mirror. They concluded that their study suggests the ability of self-awareness in dolphins rather than social behaviour. 

These kinds of studies have not been replicated after this study, however, it has been concluded that there is evidence for claiming that dolphins have passed the mirror test. Nevertheless, there are researchers that have argued that there is lacking evidence to suggest dolphins have self-awareness, and the existing evidence is not convincing enough. 

It is believed that dolphins are the second smartest animal after humans. They’re smarter than even primates. Since dolphins have a high brain-to-body weight ratio, it is understood that dolphins are capable of solving complex problems and understanding abstract concepts.

They are quick at learning and are self-aware. They are known to use basic tools for their protection. 

Dolphins also have both emotional and social intelligence. They are known to experience the emotions of grief, pain, and joy. These emotions are usually only present in animals who have complex brains.

Dolphins also have their own personalities. Some dolphins are more outgoing, extroverted and playful while others are introverted and shy. Dolphins also value social connection as they spend most of their time in groups. They teach their fellow dolphins as well as learn from them. Thus, it is believed that in larger groups, dolphins have a higher level of intelligence. 


This article answers the question “Which animal has the biggest brain on earth?” and it also highlights features of the same animal. The article compares the human brain with the animal and highlights some differences. The article will answer some frequently asked questions in the end.

Frequently Asked Questions: Which Animal Has the Biggest Brain on Earth?

Are Dolphins Smarter Than Humans?

No, dolphins are not smarter than humans. Even though dolphins use simple tools and process unique abilities that are present only in complex animals, they don’t use tools at the same level. They don’t use higher-order thinking or decision-making as compared to humans. 

Are dolphins smarter than most whales?

Dolphins and whales have roughly the same level of intelligence. 

Can a person live without a brain?

No. The brain controls all vital functioning required to live. These functions include breathing, swallowing, digestion, heartbeat, and eye movements. Without these functions, we cease to exist.

Can your brain get tired of thinking?

Yes, the brain can get burnt out by thinking. This phenomenon is known as brain fog or mental fatigue. When the brain is overstimulated it can cause dysfunctions in cognitive abilities, and affect one’s productivity, decision-making and problem-solving skills, as well as memory. It can also make it difficult for one to concentrate on daily mundane tasks.


Coghlan, A. (27 November 2006). “Whales boost the brain cells that ‘make us human'”. New Scientist. Archived from the original on 16 April 2008.

Fields, R. Douglas (2008-01-15). “Are Whales Smarter than We Are?”. Mind Matters. Scientific American Community. Archived from the original on July 27, 2010. Retrieved 2010-10-13.

Marino, Lori (2004). “Cetacean Brain Evolution: Multiplication Generates Complexity” (PDF). International Society for Comparative Psychology (17): 1–16. Archived from the original (PDF) on 2012-11-20. Retrieved 2010-08-29.

Marten, Ken and Psarakos, Suchi “Using Self-View Television to Distinguish between Self-Examination and Social Behavior in the Bottlenose Dolphin (Tursiops truncatus)” (Consciousness and Cognition, Volume 4, Number 2, June 1995)

Mortensen HS, et al. (2014). “Quantitative relationships in delphinid neocortex”. Front Neuroanat. 8: 132. doi:10.3389/fnana.2014.00132. PMC 4244864. PMID 25505387