Dwarves

Dwarves have an efficient use of body fat, their bodies having developed means of storing and burning stored calories and nutrients in an effort to keep functioning for extended periods away from food. However, this leads to a cultural emphasis on celebrating meals and eating to excess just before any major undertaking is about to begin.

Dwarves follow standard mamallian reproduction patterns, with females giving birth primarily to a single child. However, twins and triplets are known to happen, with larger births being notably rare.

The average dwarf is considered a child until they are 15 years of age, with adolescence ending in the late 20s. Developmentally speaking on a biological level they are capable of mating around 16 years of age, but most cultures emphasize the psychological development milestone of 21 years before children should be even considered.
Adulthood generally goes from 28-110 years of age, with senior age status recognized at 111 years (though some dwarves claim to be in their physical prime through 130 years).

Putting aside the various cultural influences on dwarven behavior and habits, as a species it is the subterranian nature of dwarves that influences much of what has been observed throughout the world.

Casadastraphobia seems to have a high rate of instance in dwarves, though it is most often expressed when additional stress is placed on the psyche in modern society. For some the open sky represents too many unknown variables, and they are not able to assess and stay aware of their environment as well as they would in the underground. For those dwarves which have come to terms with the differences between the surface and underground this fear can still manifest as a post-traumatic disorder or guide instinctual fear responses; find a way underground to escape the danger.

Dwarves have developed exceptional vision range to assist them in living underground. Similar to predatory cats the dwarven eye structure can adapt extremely quickly to low light. They also have structures which capture ranges of light others designate as invisible; heat, electricity, and some mana interactions provide dwarves with exceptional survivability when digging tunnels and exploring caves.

Dwarves tend to see a large amount of cultural drift, their species creating ethnic identities based on the region and styles of their underground habitats as well as on the physical adaptations that have come from phenotype development. So while many cultural events focus on the unique nature of living underground not all dwarves favor metalworking (as an example).