Hanging Out with Toads at Hahamong’na Watershed Park

Today, I went to go explore Hahamong’na Watershed Park in Pasadena. The park, named after the Indigenous Peoples who have called the area home since before the Spanish colonization of Los Angeles, is a wonderful spot to explore nature. Oak Titmice and Bushtits can be seen bouncing from branch to branch in oaks and willows. Lizards dash across paths to take refuge in native plants. Waterbirds make an occasional appearance went the reservoir is filled with water. Additionally, there is a small, basically inactive, stream that houses hundreds of toads!

Looking over the bridge that provides a wonderful view of the stream, I notice hundreds of little creatures moving about. Toads!! I went down to investigate, not even caring about all the people that would be able to look at me when they crossed the bridge. On my way down to the water, I was already noticing small toads no bigger than 1.5 inches in length. They were leaving the water and searching for some nice habitat with shade. Introducing the California Toad (Anaxyrus boreas halophilus), one of two subspecies of the Western Toad (A. boreas)!

Toads are amphibians. They begin their life cycle in bodies of water and after many promotions throughout the stages of metamorphosis, graduate as adults that live their lives on land and in water. California Toads will breed from February through July, with peak breeding activity occurring in April. California Toads are considered to be sexually mature when they reach two years of age. Males will generally breed every year, while females will breed less regularly depending on their health condition and breeding effort in past years.

Hundreds of adults will congregate to breed together, called breeding aggregations. Some externally fertilizing species, including California Toads, will engage in a mating behavior called amplexus. Male toads, who are smaller than the females, will grasp onto the female’s torso just behind the arms for a few days before egg laying begins. During this time, a female can choose if she wants to reject the male or not; even trying to get him off her back or refusing to deposit eggs if she doesn’t like him. Once the pair are solid, the female will release her eggs in shallow water (usually 6-12 inches deep) as the male fertilizes them. The male is still attached to the female at this point. Female California Toads will lay as many as 16,500 eggs during this process! The eggs will eventually attach themselves to vegetation or the water bank thanks to the gelatinous jelly that engulfs them. Neither parent will guard the eggs as they will part ways after mating.

California Toads in amplexus, Photo ©Gary Nafis, taken from CaliforniaHerps.com
The male latches onto the female and fertilizes the eggs as she releases them. These eggs will attach themselves to surrounding vegetation and along the water bank

Egg development and hatching is, at least, partially dependent on temperature and will vary as a result. California Toad eggs will generally hatch in a week or so, at which point the young tadpoles will break through their gelatinous egg casing. Not all eggs will hatch. Can you imagine hundreds of thousands of toad eggs hatching in one general area all at once?!

Toads (and frogs) begin as small, round masses with tails: the famous tadpole, and will eventually develop external gills. Then they begin to develop limbs and will lose their external gills. At this point, the toad looks like an adult except for the long tail, which is gradually absorbed into the rest of the body. Within 28-45 days (depending on temperature again), these toads will transition to life on land. They’ll take to logs, stumps, rocks, and even rodent burrows during the daytime to stay cool. When there is limited spots for hiding cover, toads will take to the water. Toads must return to a water body in order to breed. The California Toads I observed were subadults. They had completely lost their tail but have not yet reached their maximum size of 2-5 inches in length.

Toads, and amphibians in general, are wonderful bioindicators. Bioindicators are a species, or group of species, that are very sensitive to changes in the environment. Scientists will use bioindicators to determine the health of an environment over time. These changes that are monitored are usually those caused by anthropogenic means, like pollution or deforestation, but they can also be natural stressors like fire or drought.

Amphibians require a clean source of water in order to live and reproduce. Their skin is able to exchange gases with surrounding water. If the water is polluted, amphibians there will be in trouble. Therefore the presence of bioindicator species in a water body, including fish and aquatic macroinvertebrates as well, would be indicative of a water body that is (largely) free of pollutants.

I sat near the water’s edge on some rocks. All around me, I could hear rustling in the leaf litter and saw small green and brown bodies meandering about the reeds in front of me. I could see clusters of toads hanging out together in the shaded crevices of rocks and at the spots where land and water met. I could see toads elegantly swimming through the water, and others jumping from rock to rock. Down the stream a little, I saw what must have been at least a few hundred figures hopping about. Some where climbing up the rocks I now sat on, cautiously and curiously approaching me as I watched them. If they weren’t too afraid and allowed me to, I would gently pick them up and examine their blotchy coloration and speckled undersides. After making friends with the individual, I would let them continue on their journey up the hillside.

California Toad range includes western Nevada, California’s Central Valley, coastal California, and Baja California. They are dusky gray to greenish with rusty to dark brown spots where the skin glands are concentrated. They also have a white-cream colored dorsal stripe going down their back. Quite fancy if you ask me! This stripe is somewhat less developed than that of the other Western Toad subspecies, the Boreal Toad (*Anaxyrus boreas boreas*).

After a few more close encounters and a wonderful view of the other wildlife that was also exploring the water body, I picked up my stuff and ascended up the hill. I was noting all the toads that were making the climb with me. Every so many steps I took, I could hear the sound of a toad jumping out of the way, perhaps to hide. What was only a short climb for me was a journey for these young toads. As I walked through the oak groves leading to the parking lot, I saw more of my amphibian friends. I observed them exploring the new landscape they would soon call home.

A California Toad making their way to dry land

*All photos are mine unless otherwise noted

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