Biology Reference
In-Depth Information
and uses his front legs to hold her tightly in a grasp known as
amplexus.
During breeding, males have
horny pads on the first two toes of each front foot to aid them in holding the female.
The female lays her eggs during amplexus; unlike frogs, which lay their eggs in a large clump, the
toad's eggs are encased in two long, slender strings of gelatinous material. These strings can exceed
sixty feet in length and contain up to fifteen thousand eggs! Meanwhile, the male fertilizes the eggs as
they slowly emerge from the female.
Male toads aren't overly endowed with brains when it comes to mating. They often try to mate with
almost anything that floats and moves, such as sticks, leaves, and even other male toads. Indeed, a male
toad suddenly squeezed in amplexus by another male often (and justifiably) squeaks indignantly until
the offender releases him. Eventually the eager but misguided male lets go of stick, leaf, or other male
and moves on until he successfully locates a female.
Whenever submerged plants are available, toads prefer to weave their egg strings among them, al-
though the eggs aren't actually attached to the vegetation. We've often observed this behavior in our
pond. First, the mating pair, with the male on top gripping the much larger female in amplexus, appears
on the surface. After breathing for a brief period, the two dive to reach underwater growth at a depth
of two or three feet. Still plainly visible in the pond's clear water, the couple moves slowly among the
plants while continuously laying down the two strings of fertilized eggs. After perhaps five minutes,
the toads drift to the surface to breathe again, with the trailing egg strings still attached to the female.
This cycle is repeated over and over until egg-laying is done and the two toads separate.
Depending on water temperature, the eggs hatch in anywhere from three to twelve days (the warmer
the water, the shorter the time until hatching). The tadpoles, often humorously called “toadpoles,” can
easily be distinguished from frog tadpoles because they're black. They often move in schools, and feed
hungrily on algae and minuscule bits of organic debris, all the while growing steadily. Just as steadily, a
variety of predators take their toll; these include dragonfly larvae, predaceous diving beetles, fish, and
leeches.
When they are just under a half-inch long, the “toadpoles” begin their metamorphosis. As with other
frogs and toads, the tadpoles begin to absorb their tails and develop legs. This process continues for ap-
proximately two months. At the end of that time, the young are fully formed little toads, ready to leave
the water for the second part of their dual lives.
When the young toads begin their migration onto land, they present quite a spectacle. Only about a
third of an inch long, they swarm up onto the land by the hundreds, so small that at first glance they
may be confused with insects. Under normal conditions, the toadlets disperse rapidly, heading off in all
directions to seek suitable habitat. Under drought conditions, however, they may gather in moist places
to await better conditions for dispersal.
A young toad sheds its skin every few weeks while it's growing rapidly, whereas an adult dispenses
with its skin four times a year. This molt is a rather comical procedure, at least from the human stand-
point. First the skin splits. Then the toad uses its front feet to pull the old skin off, gradually stuffs the
