Travel Reference
In-Depth Information
Those beautiful blue gossamer-winged insects hovering about the streams are
dragonflies
and their smaller relatives
damselflies,
both of the order
Odonata,
meaning toothed. Some
dragonflies are also called darners for their resemblance to long, thin darning needles. They
hold their two pairs of wings horizontally, while damselflies hold their wings above the body.
They can eat as many as three hundred mosquitoes and other small insects a day. Look for
reddish-gold dragonflies in drier parts of the park.
he
water strider
(Gerris remigis)
is also called the Jesus bug for its ability to walk on water.
Its extremely long back legs enable steering, allowing the bug to spread its body weight, while
the middle pair of legs provides oar-like power.
Living in hot-spring waters is the
ephydrid fly
(Ephydra bruesi),
whose larvae live on mi-
croorganisms. The adult flies you'll see swarming in shallow hot water may not eat at all.
Among the many types of butterflies, some conspicuous ones are the small blues like the
spring azure
(Celastrina argiolus),
various shades of yellow ones called sulfurs (genus
Colias),
and the large yellow and black swallowtails of the family
Papilionidae.
In August of dry years you may be surprised at the hordes of jumping short-horned
grasshoppers
(family
Acrididae
or
Locustidae)
in every field you pass. In a glacier north of
Cooke City just outside the Northeast Entrance a great many grasshoppers have been pre-
served for some three hundred years.
Not a lot of
frogs
and
toads
live in Yellowstone, and those that live here seem to be dimin-
ishing in number. Most common is the 2- to 3-inch (5-7.5 cm)
Columbia spotted frog
(Rana
luteiventris).
These tiny animals are extremely sensitive to air and water pollution, and it has
been discovered that they're falling prey to a parasite.
Small
garter snakes
(Thamnophis elegans
or
sirtalis)
are fairly common but harmless.
Along trails in the lower altitude river valleys, you have a slight chance of seeing a nonven-
omous
bull snake
(Pituophis
genera), which may be up to 7 feet (2 m) long, or a venomous
rattlesnake
(Crotalus viridis viridis)
—up to 4 feet (1.2 m) long.
