Jumping spiders, members of the family Salticidae, are widely recognized for their exceptional eyesight, which they use to actively stalk and hunt prey. They are not ambush predators, but rather highly visual, daytime hunters who rely on rapid movement and precise jumps. When winter arrives, the common assumption that these spiders hibernate like mammals is not accurate for invertebrates. Jumping spiders do not undergo true hibernation, but they do enter a comparable state of reduced activity and metabolism known as dormancy to survive the cold months when insect food sources disappear.
How Spiders Handle Winter
The physiological state jumping spiders enter is more accurately called diapause, a genetically controlled period of arrested development that is distinct from mammalian hibernation. Since spiders are ectotherms, meaning their body temperature fluctuates with the environment, they cannot generate internal warmth like warm-blooded animals. Their metabolic rate slows dramatically as temperatures drop, allowing them to require almost no food for extended periods.
This dormant state is supported by a remarkable internal adaptation to prevent freezing. Jumping spiders produce cryoprotectants, which are chemical compounds such as glycol and specialized proteins, that circulate in their hemolymph, the spider equivalent of blood. These substances act like a biological antifreeze, lowering the freezing point of their bodily fluids and cells. This adaptation allows the spider to survive below-freezing temperatures without incurring lethal internal ice crystal damage.
The production of these antifreeze compounds is a gradual process that begins well before the first hard freeze. Their ability to minimize activity and chemically protect their tissues is the biological mechanism that allows them to bridge the resource-scarce winter season.
Triggers and Timing of Dormancy
The initiation of diapause in jumping spiders is primarily triggered by the shortening of daylight hours, a phenomenon known as photoperiod. This environmental cue is a far more reliable indicator of the changing seasons than temperature alone, ensuring the spider begins preparations even during a mild autumn. As the days grow shorter in late summer and early autumn, the spider’s biological clock signals the need for the physiological shift to dormancy.
While a drop in temperature does reinforce the need for shelter, the decreasing photoperiod is the initial and most significant signal. Jumping spiders typically begin this process in late autumn and remain in their dormant state throughout the coldest months. They will not re-emerge until the lengthening photoperiod and warming temperatures of spring signal that conditions are favorable for hunting and reproduction.
Where Jumping Spiders Seek Shelter
To enter their state of dormancy, jumping spiders must find a location that offers protection from moisture, wind, and severe temperature fluctuations. They seek out stable microclimates, which often include crevices under loose tree bark, within dense leaf litter, or deep inside rock piles. These spots offer a natural buffer against the harsh winter elements.
A critical part of their overwintering strategy involves weaving a specialized silken structure to enclose themselves. This structure is often referred to as a hibernaculum, which is much thicker and more robust than their typical resting webs. The spider uses its silk to seal itself into a tight, secure chamber within its chosen hiding spot. This retreat helps maintain a slightly more consistent and favorable temperature and humidity level.
In urban environments, they may use protected spaces on buildings, such as underneath window sills, within the cracks of siding, or inside unheated garages and sheds. The spider remains curled up and inactive inside this silken pod for the duration of the winter. Once spring arrives and the environmental cues reverse, the spider will break out of its retreat to resume its active hunting life.