Do you recognise this plant?

We try to give our children the most natural diet possible. Given that they are in semi captivity for reasons that I have often talk about. The howler monkey forages daily for food. They range through the forest searching for suitable trees for the days feeding. We have to emulate this activity to give them the most healthy and natural environment possible. Foraging also means rotation. They never feed on the same tree two days in sucession. How clever they are. They do not exhaust their supply, always leaving enough for another day. Our helpers go into the forest every day and come back with armfuls of fresh leaves, berries and fruits. The children recognize this and the happy sounds we hear from their enclosures when the boys arrive back with their days collection, is wonderful to hear. This sound tells us that we are doing the right thing. Who know better than the children themselves? This is of course in addition to the balanced diet that we give them.
Sometimes the children know better than we do. They love the leaves of the plant in our photograph. It is thorny, but this does not worry the monkeys, although I have had several sore fingers from handling it. What is its name? The locals call it 'Uña de gavilian', or 'fingernail of the hawk'. This seems like a good name, the thorns are very like the claws of the hawk. I know this because I had a young rescue hawk and her family with me for many months and her claws, grasping my hand were similar. (this story another time). I don't yet know what the children call it. What do you call it? Please tell me.