By Susan Scutti
(CNN) -- As summer heat descends, replacing balmy spring breezes, ticks are becoming active in many regions of the United States. In the coming months, some experts predict that ticks and the diseases they cause will be more abundant due to warmer winter temperatures. Worry, though, is unnecessary since prevention is possible.
Here's a simple guide to all things tick:
What are ticks?
Ticks are not insects, said Goudarz Molaei, a research scientist at the Connecticut Agricultural Experiment Station. They are arachnids, and like their relative the spider, they have eight legs when they reach adulthood. Life begins as an egg, and then ticks develop through larval and nymphal stages before reaching maturity.
"People should realize that ticks do not jump. They do not fly, and they do not drop from trees," Molaei said.
To survive, ticks must eat the blood of mammals, birds, reptiles or amphibians. If infected with bacteria, viruses or parasites, a biting tick poses a risk to human health.
According to Durland Fish, professor emeritus of epidemiology (microbial diseases) at the Yale School of Public Health, ticks have three feeding stages. The larval black-legged tick, recently hatched from an egg, is "about the size of a period at the end of the sentence." These tend to feed on birds and rodents.
Nymphs, which are "about the size of a poppy seed," and adults, which are "about the size of apple seed," also feed. Only infected ticks in either of these two stages pose a risk to humans, according to Molaei.
Lone star ticks are the exception. They sometimes bite humans in the larval stage, according to the Centers for Disease Control and Prevention.
Where are ticks found?
Ticks can be found in our backyards, under leaves, on ground cover, around walls and near structures and woodpiles where rodents and other small mammals are active, Molaei said.
"They are mainly active outdoors in wooded areas amongst shrubs, trees and tall grasses," he said.
There are several tick species in the United States, though three are most plentiful. Black-legged ticks (also called deer ticks) make their home throughout the Northeast and upper Midwest.
"Nearly 90% of ticks in the Northeast and upper Midwestern US are black-legged ticks," Molaei said. A related tick, the Western black-legged tick, can be found in the Pacific and Western regions of the country.
Dog ticks are common in the Midwest and Eastern US, with limited numbers on the Pacific Coast. This tick also inhabits the Northeast, but "it's not very common," said Molaei.
Finally, there's the lone star tick, which can be found throughout Southeastern and Eastern states.
What Illnesses are caused by infected tick bites?
"Illness depends on where you are and what kind of tick is biting you," Fish said. "And what kind of tick is biting you depends on where you are and what time of year it is."
According to Molaei, just three species -- black-legged (deer), dog and lone star ticks -- can transmit up to 15 diseases.