That night, we heard a symphony of frog sounds. Armed with a flashlight, we crept through the spiny aster plants bordering the pond. There were several different calls. We recognized the deep bass of the bull frogs, the bell-like ring of tree frogs, and the flat trill of a Gulf Coast Toad, but there were other sounds, too. What was making that bleating sound? It sounded like a goat, or maybe a lamb. Could one of our neighbor’s animals have washed under the fence?
We looked for a lost lamb or goat kid briefly, but we soon realized the bleating sound was coming from the water. Following the sound, we looked in the shallows. The water was clear and only about an inch deep. The olive-brown skin of a small frog glistened in the beam of the flashlight. It was then that we noticed its most curious feature. It had a narrow yellow line down the center of its back. It looked as if someone had dribbled a thin stream of yellow latex paint along its midline.
The yellow line, which continued under its tiny chin and across its belly, made it easy to identify. The field guide said it was a sheep frog. Not only had we never seen one before, we had never even heard of one!
We soon found out why. Sheep frogs are secretive, largely nocturnal and spend most of their time under debris or in burrows. They need high humidity and are never found more than 100 miles from the coast. The northern edge of their range is in Live Oak, Bee and Goliad counties. Their range extends southward into Mexico and Central America. Once again, we had encountered a South Texas specialty!
Because sheep frogs are seldom seen, nobody is quite sure of their status. They may be quite rare and possibly in peril. Texas Parks and Wildlife has listed them as a threatened species.
So how did we get so lucky as to have one on our farm? It turns out that a heavy tropical downpour, especially during the late summer months, triggers a reproductive response in sheep frogs. The males come out of their burrows and float about on the surface of a flooded pond. Sometimes at dusk, you can see them, their forearms resting on a stem, floating and calling that sheep-like bleat. Soon, the females join the males, and mating occurs. The male grabs on to the female locking his thumbs under her arms. As she lays the eggs (sometimes 700 of them!), he fertilizes them.
Some sources say the eggs are in strings, others say the egg mass forms a raft. But they don’t stay eggs for long. After just 12 hours, the eggs hatch into tadpoles. The fish-like tadpoles have gills and feed on plant matter until they undergo metamorphosis. At 30 days after hatching, the aquatic life of the tadpoles is over; they become air-breathing, legged, insect-eating, land animals.
This is why frogs and toads are called amphibians. They have both life (amphi-bios) styles during their lives. It is pretty amazing when you think about it.
Members of the Class Amphibia are pretty easy to distinguish from other classes of animals, but how do you tell a frog from a toad? There is no clear-cut scientific difference. In general, frogs are slim and speedy, while toads are short, plump and sluggish. Frogs can leap great distances, while toads can do short hops or just walk. Most toads have warty skin; frogs are smooth. Frogs are usually around water most of their lives, while toads can take a certain amount of dryness. Both frogs and toads must reproduce in a watery environment, however.
A sheep frog is actually a toad. It has a toad-shaped body and walks (or runs!) rather than leaps. But it has the smooth skin of a frog. Sheep frogs belong to a small family of amphibians known as the narrow-mouthed toads. The small mouth is designed to take small insects, usually ants and termites. Interestingly, the three species in this family all have a fold of skin on the back of their necks. It is just behind the eyes. These toads can roll this fold of skin forward to clear away ants that may get on their eyes while they feed.
This is the time of the year when you might see a sheep frog. Wait for a tropical deluge, go out to a pond, and maybe, just maybe, a sheep frog will be calling.
On the other hand, there is another creature that you can’t miss seeing this time of year. It’s the American Snout Butterfly.
Earlier this week, Alice Box asked me, “What are all these butterflies flying around the windows?” Indeed, there were hundreds! At first glance, they seemed small and gray, almost nondescript. But then Alice deftly caught one of the butterflies and showed me the beautifully patterned orange, white and black top sides of the wings. And we noticed another feature that was a dead giveaway: It had a snout.
The American Snout is an unusual butterfly. It is the only species with elongated mouth palps. This gives it a long-nosed or snout-like appearance. When roosting in vegetation, these butterflies lean forward with the snout touching the stem. With their wings closed, they look like dead leaves, and the snout resembles the leaf petiole. It is great camouflage.
Snouts are famous for their spectacular migrations. Literally millions of the butterflies can be on the move. Where are they going? I could not find out for sure, but in Mission, Texas, they have been observed heading northeast. Some Rio Grande Valley reports describe flights going northwest towards Austin and San Antonio. A record flight of over 6 billion snouts flew from San Marcos to the Valley during an 18-day period in 1921. North, south, east, west. I wonder if they really are migrating. Maybe these huge flights are better labeled “outbreaks” of snouts!
There is some logic to this idea. One Internet site referred to these South Texas snout migrations as “butterfly blooms” and associates them with drought-breaking summer rains. In our area, snouts can go from egg to adult in just 12 days! After a good rain, the spiny hackberry (a common brush country shrub) puts out new growth. These tender leaves are super food for snout larvae. Even if the caterpillars defoliate the bush, the spiny hackberry re-sprouts leaves. And the newly emerged adult snout females will quickly mate and lay another set of eggs! Intriguingly, most of the male butterflies will form the spectacular flights we are seeing.
So, have you seen your snouts today? Hope for a “frog-strangler” of a good rain, and you may see sheep frogs as well!