Scientists make glow in the dark monkeys
Scientists have bred a group of marmosets that glow when they are exposed to ultra-violet light.
They did it by altering the monkeys' genes. Genes are the basic building blocks of life, almost like a set of instructions for a living thing.
The achievement is important because one of the marmosets had a baby which also glows - the first time something like this has happened with monkeys.
But many people are against using animals like monkeys for experiments.
Making glowing animals might seem pointless, but some scientists think it could be very useful.
If they can get the monkeys to pass on the ability to glow to their children, they might be able to be able to get them to pass on other things, like diseases, too.
That would mean they could do research on those diseases more easily.
But others think it is wrong to breed lots of animals that we know are going to be sick.