South American Common Toad (Rhinella margaritifera)

Holobatrachus tigerinus is the largest frog in the Pakistani plains. It hibernates by burrowing in soil during winter as well as during drought.

Breeding activity is primarily confined to monsoons. The breeding males are lemon yellow in color, hence locally called "Basanti Dadoo", while females remain dull and drab-colored. The deep blue vocal sacs of male are prominent against the yellowishwhite color of the throat of the male. The call is a powerfull nasal " Cronk, cronk, cronk", which sometimes sounds like "oong wang, oong wang, oong wang" repeated several times. Calling males sit close to each other in shallow water, now and then jumping over each other. Females lurch around. One falling within the range of a male is grabbed by the male in an amplectic hold, with neighbors soon jumping on the pair and trying to dislodge them which starts much fighting, pushing, and tugging. The pair somehow moves to a quieter place where large eggs (2.5-2.8 mm diameter) are laid in several groups, each egg enclosed in a double coat of jelly. Eggs are soon attached to grass blades and often sink into the water (Khan 1969, 1996b).

Holobatrachus tigerinus is a voracious feeder; anything that is moving is bounced upon and swallowed. If needed it uses its anterior limbs to thrust larger food into its mouth. In addition to a great variety of insects, it feeds on a variety of items: mice, shrew, young frogs, earthworms, roundworms, juvenile snakes, and small birds. Vegetable matter and several odd objects are recorded from its stomach (Khan 1973). Lizards like Uromastyx (Daniel 1975), snakes: Lycodon aulicus, Ramphotyphlops braminus, Leptotyphlops sp., and young Ptyas mucosus (pers. obs.) have also been recorded from its diet.

The frog does not stay in water for a long time; it spends most of its time hiding and feeding in surrounding vegetation. On approach of danger, it plunges into deep water, stays underwater for 2-3 minutes, then returns quietly to the marginal vegetation undetected. In clear pools of water it hides under bottom gravel.

Karyotype number recorded for this species is 26 (Natarajan 1958).