Peruvian authorities announced an investigation Tuesday into thekilling of five penguins found slashed to death at a center for endangered species.The remains of the rare Humboldt penguins -- two adults and three pups -- werescattered in two bloody pools of water.Prosecutor Karin Padilla told reporters the youngest of the slain pups was just eightmonths old and that the carcasses showed their throats had been slashed.The killings reduced the number of Humboldt penguins at the rescue and breedingcenter in Puerto Eten, on Peru's northern coast, to 16.Humboldt penguins are a species of flightless birds that breed along the Chileanand Peruvian coasts, where they are believed to number no more than 50,000.Each year, hundreds of these penguins get caught in fishing nets.They are also threatened by the El Nino climate phenomenon, which occurs everytwo to seven years when the prevailing trade winds that circulate surface water inthe tropical Pacific start to weaken.