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Nocturnal animals (for example, tarsiers) and animals that live in open landscapes have larger eyes. The vision of forest animals is not so sharp, and in burrowing underground species (moles, gophers, zokors), eyes are reduced to a greater extent, in some cases (marsupial moles, mole rats, blind mole), they are even covered by a skin membrane.
Not all animals have neurons; Trichoplax and sponges lack nerve cells altogether. Neurons may be packed to form structures such as the brain of vertebrates or the neural ganglions of insects. The number of neurons and their relative abundance in different parts of the brain is a determinant of neural function and, consequently, of behavior.
Compared to that of other mammals, the pulvinar region of the brain – which helps to visually detect relevant objects – is disproportionately large and effective in the brains of primates (including humans). The concept of snakes being a special threat to humans has been confirmed by population-based studies.
Biologists have determined that humans have extremely good vision compared to the overwhelming majority of animals, particularly in daylight, surpassed only by a few large species of predatory birds. [63] [64] Other animals such as dogs are thought to rely more on senses other than vision, which in turn may be better developed than in humans ...
The aspects of animals which can reasonably be compared across species depend on the species of comparison, whether that be human to animal comparisons or comparisons between animals of varying species but near identical anatomies without a common ancestor.
The evolutionary history of the human brain shows primarily a gradually bigger brain relative to body size during the evolutionary path from early primates to hominins and finally to Homo sapiens. This trend that has led to the present day human brain size indicates that there has been a 2-3 factor increase in size over the past 3 million years ...
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Brain of a human (left), compared to that of a black rhinoceros (center) and a common dolphin (right). Elephant brains also show a complexity similar to dolphin brains, and are also more convoluted than that of humans, [20] and with a cortex thicker than that of cetaceans. [21]