Wolf spider
Wolf spiders are members of the family Lycosidae (from Ancient Greek λύκος (lúkos) 'wolf'). They are robust and agile hunters with excellent eyesight. They live mostly in solitude, hunt alone, and do not spin webs. Some are opportunistic hunters, pouncing upon prey as they find it or chasing it over short distances; others wait for passing prey in or near the mouth of a burrow.
Wolf spiders resemble nursery web spiders (family Pisauridae), but wolf spiders carry their egg sacs by attaching them to their spinnerets, while the Pisauridae carry their egg sacs with their chelicerae and pedipalps. Two of the wolf spider's eight eyes are large and prominent; this distinguishes them from nursery web spiders, whose eyes are all of roughly equal size. This can also help distinguish them from the similar-looking grass spiders.
The many genera of wolf spiders range in body size (legs not included) from less than 10 to 35 mm (0.4 to 1.38 in).[1][2] They have eight eyes arranged in three rows. The bottom row consists of four small eyes, the middle row has two very large eyes (which distinguishes them from the Pisauridae), and the top row has two medium-sized eyes. Unlike most other arachnids, which are generally blind or have poor vision, wolf spiders have excellent eyesight.
The tapetum lucidum is a retroreflective tissue found in eyes. This reflective tissue is only found in the four[3] larger eyes ("secondary eyes") of the wolf spider. Flashing a beam of light over the spider produces eyeshine; this eyeshine can be seen when the lighting source is roughly coaxial with the viewer or sensor.[4] The light from the light source (e.g., a flashlight or sunlight) has been reflected from the spider's eyes directly back toward its source, producing a "glow" that is easily noticed. Wolf spiders possess the third-best eyesight of all spider groups, bettered by jumping spiders of the family Salticidae (which can distinguish colors) and the huntsman spiders.
Wolf spiders are unique in the way that they carry their eggs. The egg sac, a round, silken globe, is attached to the spinnerets at the end of the abdomen, allowing the spider to carry her unhatched young with her. The abdomen must be held in a raised position to keep the egg case from dragging on the ground. Despite this handicap, they are still capable of hunting. Another aspect unique to wolf spiders is their method of care of young. Immediately after the spiderlings emerge from their protective silken case, they clamber up their mother's legs and crowd onto the dorsal side of her abdomen. The mother carries the spiderlings for several weeks before they are large enough to disperse and fend for themselves. No other spiders are currently known to carry their young on their backs for any period of time.
Because they depend on camouflage for protection, they do not have the flashy appearance of some other kinds of spiders. In general, their coloration is appropriate to their favorite habitat.
