This species is largely nocturnal. It has a hesitant gait, frequently stopping to smell the air. Unlike the smaller, warmer-climate species, the togedemarus that live in colder environments may hibernate in the winter. However, most wake at least once to move their nests. They are solitary in nature with mature males behaving aggressively towards each other. Occasionally a male and female may share a hibernating spot. The togedemaru is omnivorous, feeding mainly on invertebrates. Its diet includes slugs, earthworms, beetles, caterpillars, other insects, and other arthropods. The preferred arthropods are the millipedes, as well as the ground beetles, cockroaches, and tarantulas. Some reptile eggs, fruits, and mushrooms may supplement their diet.
The breeding season commences after hibernation. Pregnancies peak between May and July, though they have been recorded as late as September. Gestation is 31 to 35 days. The female alone raises the litter which typically numbers between four and six, though can range from two to ten. Studies have indicated that litter size may increase in more northern climes. The young are born blind with a covering of small spines. By the time they are 36 hours old, the second, outer coat of spines begins to sprout. By 11 days they can roll into a ball. Weaning occurs at four to six weeks of age.
Togedemarus may live to ten years of age, although the average life expectancy is three years. Starvation is the most common cause of death, usually occurring during hibernation. If alarmed, the animal will roll into a ball to protect itself. Many potential predators are repelled by its spines, but predation does occur. Remains of hedgehogs have been found in the stomachs of European badgers (Meles meles), American badgers (Taxidea taxus), striped skunks (Mephitis mephitis), red foxes (Vulpes vulpes), American pine martens (Martes americana), and European pine martens (Martes martes). A large portion of these may be from hedgehog carcasses, especially road-kill. However, hedgehogs tend to be absent from areas where badgers are numerous. The Eurasian eagle-owls (Bubo bubo), great horned owls (Bubo virginianus), and golden eagles (Aquila chrysaetos) are the only regular avian predators of this species and may even prefer them as prey. The owl, after grabbing the hedgehog by its face, tends to skin the mammal's prickly back with its talons before consumption, resulting in several hedgehog backs being found around eagle-owl/great horned owl roosts and nests.
Just like most hedgehogs, the togedemaru can roll into a tight ball in self-defense, causing all of the spines to point outwards. The hedgehog's back contains two large muscles that control the position of the quills. When the creature is rolled into a ball, the quills on the back protect the tucked face, feet, and belly, which are not quilled. However, if that doesn't work and when it is agitated, it will use its yellow cheek pouches to create small electric shocks to scare off predators as a last resort. The conservation status of the togedemaru is Least Concern due to successful conservation efforts, the togedemaru's wide range, and its tolerance to most of human activities, including being able to flourish and adapt to life in the cities and suburbs.