Jackson's Chameleon is native to high altitude forests mainly of Kenya in East Africa. There is a small population of a subspecies in Tanzania.
The name Trioceros refers to the three horns on the face (as in the dinosaur triceratops).
Only the males have these. The females of the subspecies shown have a tiny horn on the nose only.
The three horns
Horns are used for posturing rather than fighting.
The subspecies shown, T. j. xantholophus also called the Yellow-crested Jackson's Chameleon,
has been introduced to the wild in Hawaii and Florida. In the former, it is threatening the survival of a native tree snail.
Most chameleons lay eggs but Jackson's gives birth to a dozen or two live young.
Length is some 10 inches (male) . . .
. . . but can be up to 15 inches.
"Let's shake on it"