Crested lizard, Sail-fin lizard, Sailfin water lizard, Soa-soa water lizard, Ibid
The Philippine sailfin lizard (Hydrosaurus pustulatus) is a semi-aquatic lizard found only in the several islands that make up the Philippines. The Philippine Sailfin Lizard is a protected species in its native country of the Philippines as it is a target for exotic pet collectors and sought after in the international pet trade. This is largely because these lizards have unique dorsal crests (otherwise known as sailfins) that give the organism a structure similar to a sail, and the Philippine Sailfin Lizard also has very bright coloration patterns that make them attractive to the eye.
Philippine sailfin lizards are large, but males are larger than females. These lizards have a unique characteristic - their crest or sailfin, which is an upright part of their body that occurs from the base of the tail to the lower area of the back. This crest or sailfin is used not only to help with its ability to swim efficiently in water but is also thought to assist with the lizard's ability to do territorial displays and heat/cool in different environments. The crest also makes the Philippine sailfin lizard's body look like a sail with regard to its structure. Overall, the body and tail of the Philippine sailfin lizard are largely cylindrical. The flattened toes also have scale fringes that can be used for swimming and running on top of water. Males have a larger crest on their backs than the females. The males also have bigger heads, taller sails on their tails, and darker limbs. During mating season, the head of the Philippine sailfin lizard becomes violet while only the neck area of a female's crest can become violet. In terms of coloration, Philippine sailfin lizards have dark green and brown skin, and can also have yellow patches on the back side of their body and near their heads. The Philippine sailfin lizard has a flattened tail that is used to propel in water more quickly, adding to its natural born ability to be agile and swift in water to evade prey.
Philippine sailfin lizards are found across several of the islands that comprise the Philippines, including Guimaras, Romblon, Negros, and Cebu, but the lizard is not found in Palawan Island. Philippine sailfin lizards live in tropical wooded habitats near water, like rivers, riverbanks, rice fields, and mangroves. They prefer to reside near freshwater bodies of water. Additionally, Philippine sailfin lizards are often found near rocky areas close to a stream.
Philippine sailfin lizards usually spend their time singly but may gather in small groups in areas with good food sources. They are diurnal and spend most of the daytime resting in vegetation out in the sun. They lie close to bodies of water, rest in tree branches, and run across the ground to get around their habitat. They use their sailfins/scales to do territorial displays in the presence of a competitor or a predator. Juvenile Philippine sailfin lizards are excellent swimmers; they have flattened toes along with smaller mass compared to adults that enable them to run across water, similar to the basilisks. Adults do not usually retain a smaller mass and lose the ability to run across water, but they use these flattened toes to swim very effectively. Philippine sailfin lizards also have a unique physical feature - a vestigial eye (which is also known as a parietal or pineal eye) on the top of their skulls that can detect differing angles of light from the sun and are thought to be used to find a sense of direction.
Philippine sailfin lizards are omnivores. They eat plants including leaves and fruits in addition to insects and crustaceans. Juveniles prefer meat more than plants, but the balance comes as they age.
Philippine sailfin lizards breed once every year with potentially multiple clutches of eggs. Females dig relatively shallow holes in the soil near the watery habitats above the flood line, where they lay eggs that are incubated for approximately 2 months. The eggs hatch during the rainy season; the young are born with a natural swiftness and agility that allows them to evade their predators by running across the water. Females can lay several clutches a year with each containing anywhere between 2 and 8 eggs. Young Philippine sailfin lizards become reproductively mature and start to breed when they are 2.5-3 years old.
The main threats to this species include habitat loss, hunting for food, and collection for the pet trade.
The IUCN Red List and other sources don’t provide the number of the Philippine sailfin lizard total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, but its numbers today are decreasing.
