Summary:
A caretaker has resigned after two monkeys died in a heat-related incident at a zoo in the US state of Louisiana.

Full article:
Two small endangered monkeys died because a caretaker 'overlooked' them and left them out in the cold at a zoo in central Louisiana. The cotton-top tamarins, which weigh less than a pound, were left out in the cold last week at the Alexandria Zoological Park. A third monkey survived the exposure. Cotton-top tamarins are native to Colombia's northern tropical forests and there are only around 6,000 left in the world (stock image) The monkeys weigh less than one pound each and need temperatures of 76 to 85 degrees. The high last Wednesday in Alexandria was in the 50s. Thursday morning's low was in the teens. It's not clear exactly how the monkeys were overlooked or whether they had an outdoor 'nest box' with a heating unit. Public Works director, David Gill, told the Washington Post: 'The employee who was initially on administration leave and had been removed from any animal care, has resigned. 'This appears to have happened as a result of human error and not a system problem.' City spokeswoman Cynthia Jardon wrote in an email Tuesday that she couldn't provide details because of an ongoing investigation. The caretaker resigned Monday and there have been calls for a federal investigation into the deaths. The monkeys' natural habitat is in Colombia's northern tropical forests and there are only around 6,000 of the cotton-top tamarins left.