Humans, also referred to as "human beings" and by their scientific name Homo sapiens, are the only extant member of the genus Homo. They are closely related to the great apes, with DNA about 98.7 percent identical to that of chimpanzees and bonobos. They differ most notably in having a more highly developed brain and hands suitable for precision tasks, although they are generally much weaker physically.
Humans possess complex symbolic language and rich cultures, allowing them to transmit knowledge across generations. They also rely on sophisticated tools and technologies that accumulate and improve over time, shaping their societies and environments. Humans also display exceptionally high variation in facial features compared to other animals, aiding individual recognition in social groups.
Humans are also unusually numerous for a large mammal, with a global population in the billions, vastly outnumbering their closest relatives the great apes, whose populations are only in the tens, or at most, hundreds of thousands.
Among vertebrates, only a few species likely have numbers of individuals comparable to or exceeding those of humans, mainly some fish, such as anchovies, whose numbers may reach into the trillions, and some rodents, especially the brown rat and the house mouse, with numbers comparable to or possibly exceeding those of humans. The domestic chicken population is estimated in the tens of billions worldwide, although this is artificially maintained for human consumption.
In terms of biomass, humans constitute roughly one third of all mammals, and, together with their livestock, account for about 95 percent of mammal biomass, leaving only a small share for the total of all wild mammals.