================================================== | Distance between | Distance between | Snout-vent | | base of fangs | fang punctures | length | |------------------+------------------+------------| | 7.7 | 13.0 | 400 | | 8.7 | 14.0 | 575 | | 10.0 | 22.5 | 526 | | 11.0 | 18.0-19.0 | 590 | | 12.0 | 18.0 | 793 | | 13.0 | 17.0, 20.0 | 558, 612 | | 15.5 | 23.5 | 800 | | 16.0 | 24.0 | 800 | -------------------------------------------------- HABITAT AND LIMITING FACTORS Although usually associated with swamps and lowlands along river bottoms, the cottonmouth lives in a variety of habitats ranging from salt marshes to cool, clear streams and from sea level to an altitude of 2300 feet. Shaded, moist areas either in or beside shallow waters are preferred, but cottonmouths occasionally wander as far as a mile from water. In the pine-oak forests of Nacogdoches County in eastern Texas cottonmouths and copperheads are probably the most abundant species of snakes. Specimens have been collected near Nacogdoches in ponds, swamps, clear and fast-running streams with rock bottoms, and sluggish muddy streams. On the Stephen F. Austin Experimental Forest numerous cottonmouths live in a swamp until around mid-July, when it becomes dry. A small stream west of the swamp seems to be used as a migration route to and from the swamp. Slightly more than a mile downstream cottonmouths are common in a bottomland area. The ground is always moist and no undergrowth occurs; a few small clear springs produce shallow trickles that run into a swamp. Cottonmouths can often be found here, lying in or beside the small trickles. I have seen cottonmouths in various types of aquatic habitats in Brazoria County. In most places in this area, cottonmouths are found in association with one or more species of water-snakes (including _Natrix cyclopion_, _N. erythrogaster_, _N. rhombifera_, and _N. confluens_), which greatly outnumber the cottonmouth. Interspecific competition may be reduced somewhat by cottonmouths sometimes feeding on water-snakes. The numerous statements in the literature concerning the habitat of the cottonmouth can be summarized most easily by the following short quotations: _Agkistrodon piscivorus piscivorus_--"Marshes and lakes; ponds and streams with wooded shores; low country near water; roadside ponds; drainage ditches; coastal 'banks'; keys; some Gulf coast islands; mangrove swamps." (Wright and Wright, 1957:919.)