The trunk, or proboscis, is a fusion of the nose and upper lip, although in early fetal life, the upper lip and trunk are separated. The trunk is elongated and specialised to become the elephant’s most important and versatile appendage. It contains up to 150,000 separate muscle fascicles, with no bone and little fat.
The pygmy hippo is reclusive and nocturnal. It is one of only two extant species in the family Hippopotamidae, the other being its much larger cousin the common hippopotamus (Hippopotamus amphibius). The pygmy hippopotamus displays many terrestrial adaptations, but like its larger cousin, it is semi-aquatic and relies on water to keep its skin moist and its body temperature cool.
Musth or must is a periodic condition in bull (male) elephants, characterized by highly aggressive behavior and accompanied by a large rise in reproductive hormones. Testosterone levels in an elephant in musth can be as much as 60 times greater than in the same elephant at other times. However, whether this hormonal surge is the sole cause of musth, or merely a contributing factor, isunknown. Scientific investigation of musth is problematic because even the most placid elephants become highly violent toward humans and other elephants during musth.
