By Sarah Tate May 18, 2021 The world's most endangered canine species grew a little bigger over the weekend when the North Carolina Zoo welcomed three litters of American Red Wolf puppies, for a total of 12 pups, over the course of three days, WCNC reports. According to the zoo, the critically endangered species only has 15 to 20 red wolves that remain in the wild, and all in eastern North Carolina. The new additions bring the zoo's total number of wolves in its breeding program to 36, the second largest pack in the U.S. behind Point Defiance Zoo and Aquarium in Tacoma, Washington. "Three must be the lucky number, because we are so happy to share that we have 3 litters of red wolves for a total of 12 puppies," the zoo announced Monday (May 17).