Ditmars' Horned Lizard

Phrynosoma ditmarsii, (Stejneger)

Colouration: Sandy red, with obscure, dark cross-bands on central portion of the back.
Dimensions: Total Length (Male Specimen). . . . . 4 inches.
Distribution: But two specimens are known--a male and a female. They were taken in Mexico, in the state of Sonora, a short distance south of the southern border of Arizona.
Habits: The writer has observed but one living specimen. It was an interesting creature and lived about a year. It would feed only when the sun was shining brightly upon the sand of the cage, when it took large ants, grasshoppers, crickets and mealworms. The ants were snapped up in a manner appealing much to the habits of the true toads--namely, the bending of the head downward toward the prey, the instant protrusion of a pink tongue and the sudden disappearance of the insect in a movement so quick that the human eye was unable to follow it. This movement was attended by a single gulp on the part of the reptile. There was no subsequent mastication. The swallowing of larger prey was attended by a curious series of manoeuvres. There was the same momentary, downward pointing of the head and the prey was conveyed to the jaws like a flash, but as it was too big to be drawn entirely into the jaws by the action of the tongue, it was roughly masticated and worked into the mouth by an extraordinary process of wiping the jaws from one side to another upon the sand and with such vigor and rapidity that numerous grains were thrown against the glass sides of the cage. After swallowing a large insect, the reptile assumed an astonished expression, opening the eyes widely, then nodding the head violently up and down, six or eight times.

In considering this recently discovered species, we arrive at what might be termed the second group of horned lizards. The general size of the species is rather smaller than those previously described, while the scalation of the body is finer. Thus these species appear much smoother and less bristling than the former lizards. With several of the species, the ear drum is covered with granular scales and is not visible externally. Like that portion of the genus already treated this latter portion is so arranged that the species with rudimentary horns precede those with well developed head spines.

The present species is practically hornless and has the widest head of any of the genus. The head is considerably wider than long. The region of the temple is produced into a flat, crest-like prominence, bordered in the rear with large scales, but no actual horns. On the lower jaw are two rows of enlarged, very keen-edged plates, which, instead of being parallel with the lower ?lip plates as with other species, extend obliquely from them, downward. The central chin scales are small and of uniform size. The scales of the abdomen are strongly keeled.

The back of this species is quite smooth, and sprinkled with charged, keeled scales laying quite flat against the skin. There is no margin of spiny scales. Lacking the head spines and bristling, spiny exterior of most of the species, the aspect is very toad-like.

The tail of the female is much shorter than the male.

Width of Body. . . . . 1 5/8 inches.

Width of Head. . . . . 1 1/8 inches.

Length of Head. . . . . 7/8 inches.

Although the general demeanour of the horned lizards is timid and inoffensive, occasional specimens make ludicrous attempts at self defence. The present specimen was curious in this regard. When annoyed it would arch its back, point its snout downward, then make jumps of fully an inch from the ground, from this position, each jump being accompanied by a miniature hiss, which sounded like a sneeze. The performance was altogether clown-like and far from alarming. When the lizard discovered that its efforts were unsuccessful in driving the intruder away, it resorted to flight, in a scamper for a dark corner. Late in the afternoon it so buried itself in the sand, that only its nostrils and the crown-like top of the head were visible, and these so closely matched the colour of the sand that a close inspection was necessary to find it at such times.

The animal died from inflammation of the intestines, a condition that kills many of the captive horned lizards and may result from the change of environment, from the absolutely dry and warm sands of the desert--the home of most of the species--to the general clamminess that pervades sand or gravel in our damp, Eastern climate, unless the bottom of the cage is heated by steam or hot water pipes--rather a difficult provision in a private collection.

The rarity of this horned lizard might be accounted for in the consideration of its relatively smooth skin and absence of head spines, rendering it an easy prey for various snakes. Thus the general abundance of those species with bristling body spines and long horns upon the head might also be explained.