Pygmy hippopotamus occur. The common hippopotamus gives birth and mates only in the water, but pygmy hippos mate and give birth on both land and water. Young pygmy hippos can swim almost immediately. At birth, pygmy hippos weigh 4.5–6.2 kg (9.9–13.7 lb) with males weighing about 0.25 kg (0.55 lb) more than females. Pygmy hippos are fully weaned between six and eight months of age; before weaning they do not accompany their mother when she leaves the water to forage, but instead hide in the water by themselves. The mother returns to the hiding spot about three times a day and calls
Kozlov's pygmy jerboa April and May and the litter size averages three to five young. Kozlov's pygmy jerboa has a wide range and is a common species in suitable habitat. The population trend is not known but it is presumed to have a large total population and is present in several protected areas. No specific threats to this jerboa have been identified, and the International Union for Conservation of Nature has assessed its conservation status as being of "least concern". Kozlov's pygmy jerboa Kozlov's pygmy jerboa ("Salpingotus kozlovi") is a species of rodent in the family Dipodidae. It is found in northwestern China