Adult male nurse shark cruising the shallows. Wes Pratt, Mote Center for Shark Research Sharks range in lifestyle and demeanor from the fast, aggressive shortfin mako to the more relaxed and sedentary bottom dwelling sharks. Although all sharks are carnivorous, meaning they eat other animals, nurse sharks fall into a category of laid back, easy-going sharks that prefer to swim awhile and then rest awhile. Nurse sharks (Ginglymostoma cirratum) may in fact be considered the "couch potato" of the shark world. This label, however, is not meant to imply that their lives and behaviors are simple and always relaxed; quite the contrary! But they do slow down, swim locally, and associate — sometimes in cozy piles — with other similar-sized nurse sharks in the shallow warm seas they usually inhabit. Such behavior allows time for shark socializing and fosters the development of interesting group behaviors. Female nurse sharks in a social group. Wes Pratt, Mote Center for Shark Research Nurse sharks are typically found in tropical to subtropical waters in coral and rocky reefs, on grass and sponge flats, and among the roots of mangrove shorelines. In warm tropical waters, they are common, mostly nocturnal, inshore, bottom-living sharks. The range of nurse sharks in the Atlantic Ocean extends from Rhode Island to southern Brazil, including the entire Caribbean and Gulf of Mexico. In the eastern Atlantic their range extends from the Cape Verde Islands to Gabon along the African coast. Their range along the American Pacific coast from extends from Baja California in Mexico to Peru. In general, their depth range extends from the intertidal zone down to a depth of at least 40 feet. Three female nurse sharks refuged next to the beach. Wes Pratt, Mote Center for Shark Research Nurse sharks typically are born during the winter. They are about 1 foot in length at birth and grow 4 to 6 inches a year in length, less as they get larger. The time to reach adulthood and mating can be as long as 15 to 20 years, at which time they are 7 to 7.5 feet in total length. The maximum length recorded is 13 feet but no one has reliably measured a nurse shark longer than a bit over 9 feet. Although sharks are diminishing in number and the biggest ones are the hardest to catch, a few larger nurse sharks may still exist in remote areas as yet unnoticed by science. Newborn nurse shark pup. Wes Pratt, Mote Center for Shark Research Nurse sharks are easily identified by the small mouth located forward of the eyes and just under the broad snout. The mouth is bracketed by two sensory barbels. Most nurse sharks range in color from light to dark brown, though rare albino nurse sharks also exist. Young nurse sharks have little black spots along their backs. The ventral surface (belly) is a creamy white. The teeth are small but exceedingly sharp and, like the teeth of all sharks, are replaced by moving slowly forward as if they were on a conveyor belt. Older teeth slough off while the shark feeds and are replaced by sharper, slightly larger teeth. Adult female near coral reef. Wes Pratt, Mote Center for Shark Research The success of nurse sharks as a species results in part from a wide diet of fish and reef invertebrates, caught mostly at night by suction feeding in crevices. Young nurse sharks will patrol the flats day or night on a rising tide in search of foraging crabs and octopi. They hunt by brushing the bottom with the two oral barbels, often twisting back to lunge head first into the bottom in pursuit of prey. Water is powerfully sucked in through the mouth, with silt and sand puffing out of the gills as the tail slaps the surface. The shark's tough hide and smooth tile-like scales keep damage from impact to a minimum. Crabs, shrimps of all kinds, and lobsters are taken whole from under the reef. Nurse sharks will often snap the lobster's head off with a shake, consuming the tail immediately. Small conch also are a favorite; the sharks use their powerful jaws to break open the shells. Photographing nurse sharks mating in shallow water. Adults are commonly 8 to 9 feet long and mate in Florida waters from May to July. Wes Pratt, Mote Center for Shark Research Knowingly or not, people swim near nurse sharks every day without incident. Attacks on humans are rare but not unknown and a clamping bite typically results from a diver or fisherman antagonizing the shark with hook, spear, net, or hand. The bite reflex is such that it may be some minutes before a quietly re-immersed nurse shark will relax and release its tormenter. The small teeth seldom penetrate deeply but are razor sharp. Holding still reduces damage to both shark and man. Leaving sharks alone is the best tactic. Nurse sharks were caught in directed fisheries in the 1940s for their hides (shark leather) and liver oil and killed as by-catch in long lining and trap and net fisheries. They are regarded as too sluggish for sport fishing and are undesirable for food or the fin trade. The flesh of sharks and other long-lived fish species concentrates mercury and other toxins and should be avoided. Nurse sharks have been kept by aquarists and researchers as they are hardy, live a long time, and are quick learners. However, keeping them in home aquaria is not wise as they will eventually reach 9 feet long! They are more valuable to all of us alive and free in the ocean. More importantly, with the help of the nurse shark as an easily observed and studied species, we are learning the importance of sharks in tropical ecosystems. Their apex position in the ocean's energy flow makes them equivalent to the lions and tigers of terrestrial systems. By studying the nurse and other shark species, we are just beginning to understand how the life history and activities of these sharks is important in balancing oceanic food webs and keeping coral reef ecology healthy and diverse. Next page... ||||| BOCA RATON, Fla. (AP) — News reports say a 23-year-old woman was bitten by a small nurse shark in Boca Raton. 
 
 The South Florida Sun-Sentinel http://bit.ly/22bGTSu reported the woman was taken to the hospital by ambulance Sunday with the shark still attached to her arm. 
 
 A spokesperson for the Boca Raton Ocean Rescue told the newspaper the woman remained calm and there was a little blood. A splint board was used to support the woman's arm and the shark as she lay on the stretcher. 
 
 The Boca Raton Regional Hospital operator told the AP that the woman had been treated and was in the process of being released Sunday afternoon. ||||| It was an alarming sight for beachgoers when a woman walked out of the water with a nurse shark biting a meaty portion of her right forearm. 
 
 And no matter what she did, the 2-foot shark refused to release its bite. Even when it died. 
 
 Paramedics ultimately took the woman — with the dead shark still attached to her arm — to Boca Raton Regional Hospital on Sunday afternoon, according to Boca Raton Ocean Rescue. 
 
 The woman was in stable condition, officials said. 
 
 "The shark wouldn't give up," said Shlomo Jacob, of Boca Raton, among the beachgoers who looked on. "It was barely breathing but it wasn't letting go of her arm, like it was stuck to her or something." 
 
 A nurse shark bit a woman on the beach Sunday afternoon in Boca Raton. 
 
 As the commotion unfolded, swimmers scampered out of the water, suddenly unsure of what other dangers may lurk. 
 
 Ocean Rescue Capt. Clint Tracy saw the woman and the shark as they were put into an ambulance at Red Reef Park about 1:30 p.m. "I have never seen anything like it," Tracy said. "Never even heard of anything like this." 
 
 Beachgoers said one or more people were antagonizing the nurse shark in the water. Tracy, the Ocean Rescue captain, said he didn't know how the woman came in contact with it. 
 
 Nate Pachter, 11, of Boca Raton, said he and his cousin were snorkeling when he saw the group "holding the shark by its tail. They were messing with it." 
 
 Courtesy Boca Raton Fire Rescue A woman at the beach in Boca Raton near the 1400 block of North Ocean was was bitten by a small nurse shark on May 15, 2016. A woman at the beach in Boca Raton near the 1400 block of North Ocean was was bitten by a small nurse shark on May 15, 2016. (Courtesy Boca Raton Fire Rescue) (Courtesy Boca Raton Fire Rescue) 
 
 "Sharks are like the most humane thing ever," Nate said later, as he sat with his parents on the beach. "So it wouldn't bite them if they hadn't been messing with it." 
 
 It was about 1:20 p.m. when the woman, in a turquoise-colored two-piece, appeared near Lifeguard Station No. 8, with the shark attached to her. 
 
 The woman remained calm, and there was little blood, according to Tracy. 
 
 A male companion was by the woman's side holding the shark, but as the minutes passed and the crowd grew, she became unsettled. When paramedics arrived, they gave her oxygen, witnesses said. 
 
 A splint board was used to support the woman's arm and the shark as she was placed on the stretcher to take her to the hospital, Tracy said. 
 
 The woman's name hasn't been released, so she couldn't be reached for comment. 
 
 Lifeguard Dylan Narcowich was on duty in Tower No. 8 and responded. He said he previously had seen the woman and her companion swimming near a submerged rock pile about 60 feet from shore. 
 
 "There's a rock pile where she was at and there are two more over there where they kind of hang out," said Narcowich, referring to the sharks that occasionally swim near the submerged formations. 
 
 Nurse sharks are common in offshore Florida waters and can grow up to 14 feet in length. 
 
 They are able to breathe while remaining still by pumping water through their mouths and out their gills, and are sometimes seen stationary on the ocean floor, according to researchers. 
 
 They are also known for having strong jaws filled with thousands of tiny, serrated teeth. 
 
 "Knowingly or not, people swim near nurse sharks every day without incident," according to the National Park Service. "Attacks on humans are rare but not unknown and a clamping bite typically results from a diver or fisherman antagonizing the shark with hook, spear, net or hand. 
 
 "The bite reflex is such that it may be some minutes before a quietly re-immersed nurse shark will relax and release its tormentor," according to a National Park Service brochure prepared for visitors to Florida waters. "The small teeth seldom penetrate deeply but are razor sharp. 
 
 "Holding still reduces damage to both shark and man. Leaving sharks alone is the best tactic." 
 
 bballou@sun-sentinel, 954-495-5310 or @briballou
– A Florida woman hospitalized for a shark bite Sunday didn't need to describe the shark that bit her—because it was still attached to her arm. The 23-year-old woman had been bitten on the right arm by a small nurse shark that wouldn't let go even after a bystander killed it, the Palm Beach Post reports. A Boca Raton Regional Hospital spokesperson tells the AP the woman was treated and released on Sunday afternoon, having presumably had the 2-foot shark removed from her arm. Witnesses say before the bite, the shark had been antagonized, possibly by the woman and her companion, who were seen near a submerged rock pile where nurse sharks are known to hang out. People were "holding the shark by its tail. They were messing with it," 11-year-old Nate Pachter, who had been snorkeling nearby, tells the South Florida Sun Sentinel. The species has a strong bite and large numbers of very sharp teeth, but it is so laid-back it is "considered the 'couch potato' of the shark world," according to the National Park Service. "Attacks on humans are rare but not unknown, and a clamping bite typically results from a diver or fisherman antagonizing the shark with hook, spear, net, or hand," an NPS fact page states. "The bite reflex is such that it may be some minutes before a quietly re-immersed nurse shark will relax and release its tormentor." (On the other side of the country, countless tiny red crabs are washing up on California's beaches.)