Life History



Due to the rarity and semi fossorial nature of this species, little life history information exists. The Puerto Rican crested toad was first described in 1868 by Cope. The crested toad was thought extinct from 1931 to 1967 until its rediscovery in the northern part of the island in Isabella and in 1974 was found in Quebradillas (Estremera, 1990). With the exception of two populations in Puerto Rico, known historic populations were represented by a small number of voucher specimens randomly collected up to the late 1970’s. The toad has not been seen on Virgin Gorda for over 30 years and the last specimen was collected there in 1964 (USFWS, 1992). In 1984, the southern population that exists today was discovered in Guánica Commonwealth Forest (Moreno, 1985) and in 1987, the crested toad was listed by the USFWS as a threatened species. By this time, the species had been reduced to two populations in Puerto Rico, one in the north at Quebradillas and one in the south at Guánica. Mitochondrial DNA analyses suggest that these two populations have been separated for up to 1 million years (CBSG, 2005).The toads were last seen in Quebradillas in 1991 and the only known toads left from this population exist in captivity. Population estimates at Guánica over the past 25 years have fluctuated from 300 to 3,000 individuals (Lentini, 2003; CBSG 2006; Canals, 2007 unpub, data).

Since 1984, data collected at the Guanica site show that reproduction events for the toad are sporadic, coinciding with heavy rain events with at least 5 cm (2 inches) of water accumulation. Breeding has been documented every month of the year except for March (Canals, 2007 unpub. data). Females are thought to lay eggs only once per year. After it rains, males gather at the temporary pond and call females. It is suspected that light rains (less than 7 inches) attract toads within 1-2 kilometers (1 mile) from the pond and heavier rains (7-13 inches) are sufficient to attract the entire breeding population from up to 3 kilometers (2 miles) (USFWS, 1992). During amplexus, the females lay long, black strands of eggs amongst vegetation. It has been reported that a single female can lay up to 15,000 eggs (Rivero, 1998). Shortly after, the females leave the pond and the males remain for 1 to 2 days before dispersing. Eggs hatch after 24 hours and the tadpoles metamorphose within 18-25 days. It has been reported that some toadlets were found as far as 4 linear kilometers (2.5 miles) from the breeding pond (USFWS, 1991).

A radiotelemetry study conducted by the Toronto Zoo in 1990, showed that post reproductive toads moved on average 125 m (410 feet) a night for the first four days and traveled a maximum distance of 2 k (3.2 miles). After the initial period of intense movement, toads moved no more than about 10 m (32 feet) (Johnson 1999). It was also observed that toads were capable of climbing vertical rock faces to seek shelter in holes within the limestone that were at least 45 cm (18 inches) above ground. Toads would often return to the same retreat they had previously used days before.  Additional observations of PRCT toad refuge sites and defensive behavior (Pacheco and Barber, 2013) describe adult crested toads using the top of their heads to block entrance holes and using alternative refugia, such as abandoned bird and tarantula holes in soil, in addition to holes in karst rock. One toad mentioned was found in a hole on a steep slope as high as 2.13 meters above the ground (see photo below).

PRCT in abandoned hole

During a habitat characterization study conducted at Guanica National Forest, average microclimate temperatures for the toad ranged from 81 to 85 F and relative humidity levels varied from 66% to 83% (CBSG, 2005).

Diet studies for crested toads in the wild have not been completed. However, toads most likely feed on a variety of insects including abundant invertebrates found in leaf litter including ants and beetles.  Tadpoles feed primarily on vegetation, but have been observed feeding on dead conspecifics, carcasses of anoles, scorpions and millipedes (Barber, personal observation).