For every kitten born to a stray, a cat in a shelter is less likely to be adopted and more likely to be euthanized. That, at least, is a popular refrain from animal advocacy groups that support spaying and neutering homeless cats as a measure of population and disease control.
The Push to Neuter
Not long ago, animal overpopulation mainly was managed by rounding up and euthanizing strays. The 1990s saw a large push toward trap/neuter/return programs that sought to sterilize homeless animals -- particularly cats, which tend to join and create feral colonies -- and return them to the outdoors. The aim of TNR programs was to stop wild cats from being able to generate more wild and homeless animals that would end up in shelters to be euthanized.
Animal advocacy groups such as the Humane Society, ASPCA and Dumpster Cats Rescue League suggest TNR programs reduce suffering among strays by not creating new strays. One female cat can produce as many as nine kittens per litter, and she often will bear them in alleys and trash containers. Dumpster Cats also reminds that unsterilized cats are promiscuous, and as they mate with others, the chance of catching or spreading diseases such as feline leukemia, rabies, feline herpes and feline AIDS increases.
While most animal groups advocate TNR programs, some have questioned whether the practice is doing any good. A 15-year look at TNR by the Humane Society finds that despite "aggressive surgical spay-neuter campaigns, humane education, and legislative efforts, only modest progress has been made in reducing the staggering numbers of 'surplus' pets," and millions of strays are still being euthanized in U.S. shelters annually, at an estimated cost of $2 billion.
Strays Become Feral
Stray cats are domesticated and generally friendly and sociable around people. But if left on their own long enough, most strays will become feral. They will join feral colonies and produce litters of feral kittens. People for the Ethical Treatment of Animals warns that feral cats tend to live short lives exposed to dangers such as weather, disease and predators. Spaying and neutering outdoor cats helps to stop new cats from joining or forming feral colonies.