Spanish Version Located Here

Reptiles are cold-blooded and have to depend on sources of warmth outside of their own bodies.  This explains why you can often see western fence lizards sitting on the top of fence posts, rocks or logs – they are warming themselves in the sun.  Western fence lizards have bright blue throats and bellies, and the males communicate with each other by doing “pushups”, lifting themselves up to show off their bright colors. These very common lizards provide a valuable service; they are often bitten by ticks and their blood kills the parasite inside ticks that causes Lyme disease.  This has the effect of greatly reducing the risk of contracting Lyme’s disease in areas with healthy Western fence lizard populations.

_{Western fence lizards can often be seen perched atop fence posts.  Photo credit: ©2008 William Flaxington (CC BY-NC 3.0) license.} 

Although southern alligator lizards are also quite common, they are hard to find since they actively hide in dense grasses and other vegetation.  You can tell them apart from western fence lizards because they lack a colorful underside and they are much larger, with a triangular head and powerful jaw.  Alligator lizards are voracious hunters.  They eat insects, spiders (including black widows!), snails, other lizards, and young mice.  They have even been known to climb trees and eat bird eggs.  Alligator lizards protect themselves from predators by hissing and biting.

_{The southern alligator lizard is aptly named since it looks a bit like a miniature alligator.  ©2008 William Flaxington (CC BY-NC 3.0)}

Our only native aquatic turtle, the western pond turtle, is usually found near water where you can often see them perched on the top of logs basking in the sun.  Female turtles lay their eggs on land, traveling up to a half mile from water to find a south-facing slope.  They dig shallow holes and lay clutches of 3-13 eggs, which incubate for three or more months before hatching.  The tiny 1 inch turtles have to make their way back to water on their own, an often perilous journey.  Western pond turtle populations are declining and are listed as a Species of Special Concern by the California Department of Fish and Wildlife.

_{The western pond turtle can often be seen perched atop a log along creek banks in Centennial Park.  ©2015 William Flaxington (CC BY-NC 3.0) license}

_{Gopher snakes are quite common in Centennial Park and are harmless to humans.  Photo credit: ©2009 William Flaxington (CC BY-NC 3.0)}

Other snakes you may see in the Park include the common kingsnake (dark body with bands of creamy yellow), garter snakes (pale yellowish or reddish stripes running the length of the body), and racers (light brown with a pale blue underside), all of which help keep rodent populations under control.

Amphibians are also cold blooded, but they differ from reptiles in their dependency on water.  Although amphibians can live as adults in terrestrial habitats, they must lay their eggs in water in order to successfully reproduce. 

The most common amphibian at Centennial Park is the Pacific treefrog and every spring thousands emerge from eggs laid in the Horse Creek tributaries and associated wetlands.  You can often hear them at dusk – a loud chorus of “krek-ek” calls.  These small greenish-brown frogs can be identified by their dark eye stripe.  Their tiny toes end in suction cups which allow them to climb trees and other vegetation in search of insects to catch with their sticky tongues.

 
_{Although Pacific tree frogs are tiny, their chorus can be quite loud in the evenings.  Photo credit: ©2013 John P. Clare (CC BY-NC-SA 3.0}

Also present in the Park are western toads.  They can be differentiated from frogs by their warty skin and the faint white stripe that runs from their forehead down their back.  Toads also tend to walk, instead of hop. Western toads hide in loose soil during the day and are most active at night when they creep about searching for insects to eat.  Toads excrete poison from their warts, which helps deter predators from eating them.

 
_{The western toad is much larger than the Pacific tree frogs and it walks (rather than hops) to get around.  Photo credit: ©2015 William Flaxington (CC BY-NC 3.0)} 

We are lucky that so many reptiles and amphibians live in Centennial Park.  Please respect them and help protect their environment.  While it is fun to observe and photograph, you should never pick up or corner any wild animal, since they may think you are a predator and try to protect themselves. 

This information has been provided by the City of Vacaville in partnership with the Solano Resource Conservation District.  It was last updated on December 31, 2019.