* bristles, which are long hairs usually used in visual signals, such as the mane of a lion;
* velli, often called "down fur", which insulates newborn mammals; and
* wool, which is long, soft, and often curly.

Hair length is unimportant in thermoregulation, as some tropical mammals, such as sloths, have the same fur length as some arctic mammals but with less insulation; and, conversely, other tropical mammals with short hair have the same insulating value