Male or Female?

A warning. This is a long post. Yesterday we received an e-mail from Karen in Costa Rica and I have enclosed here the relevant correspondence. The text makes the post self explanatory, with posts from Karen and replies from me. We are delighted to make the acquaintance of Karen and George and to the Black Howler whose name has not yet been settled. I have posted before about the real difficulty people experience in distinguishing between male and female howlers. I hope that with this beginning I will be able to pass on news of this handsome fellow often. Well done Karen and family for caring for this little boy. Top left picture the monkey at the office of the Veterinarian. You can see the testicles that caused the query. Right shows a female's organs. Bottom the Black Howler with a swollen hand showing.

Greetings from Southern Costa Rica. Congratulations on your work with primate rescue. I happened upon your blog, Forget-me-not, while searching for answers. An injured howler monkey (Alouatta palliatta) recently appeared at my home, which is at the edge of the jungle. My son and I managed to get it to the local vet and it's now healing well. I say it, because we're still not positive what sex it is. While sedated , we could examine it at length and the white testicles were very obvious, so we assumed it was a male. But it has no penis and only one hole between the balls and tail, so we were very confused. The vet had no experience with howlers. Thanks to your blog and photo, I'm now thinking it must be a female. It hasn't howled, although it listens intently each time it hears a male howling nearby. We're hoping its hands and feet will soon be well enough that it can return to the wild. I'm just having a hard time calling it a female with those testicles. Is this a common condition among howlers? Could you post a photo of a male so we can compare. I can't seem to find anything online. The vet and I would be very grateful. I've attached a photo of my son and the vet with the howler. The vet took a picture of the monkey genitalia, in case you need a better shot. Thanking you in advance for any help you can give us.
Sincerely, Karen G. Davies
Pinuela de Osa, Costa Rica

Dear Karen. Thank you for the note and the picture. You can safely call him 'he'. It is true that the female howler does have external genitals but they are small. What is more, as the animal gets older, the appearance changes and then there is no doubt. Your monkey is an adult and he has normal genitals for a male. When the male is sick or unhappy, the penis retracts into the hole you mention. Believe me when he is feeling better you will see what he has. I am a little worried about returning him to the wild. What kind of injuries does he have? Hands and feet sound as if he has been fighting. Typically, young adults are thrown out of the tribe by the dominant male and sometimes killed. Is there no way you could encourage him to stay with you? They like human company when they lose their fear of you. Please Karen and son keep me in the picture and lets me know how he gets on. You don't really need the heavy gloves for long. You will know he is better when he wants to sit on your shoulder. Your question is very relevant to the story on my blog. I would love to publish your photograph and your letter. Please tell me if I have your permission. This will help others with the same doubts. God bless you for caring for this little fellow.

Philip at Canaote

p.s. Get the vet to check for parasites the faeces or take a sample to your local clinic. Philip,

Thank you so much for the quick response. I guess we have a lot to learn about our furry friends. Yes, the vet gave him a shot for parasites. Three of his hands were swollen and infected, but with antibiotics he's getting better each day. He eats well and is more active in the small cage. If it looks like a long period of recuperation will be necessary, we'll make a larger enclosure. We won't let him loose until we're sure he can function well on his own. We'll let you know how he progresses and you are welcome to use the letter and photos on your blog. I'll look forward to the photo of the male.

Thank you again for all your help. And good luck with your projects.

Karen and George Davies

From the size of your male friend I would say he was about 5 years old. Being male he will have quite a strong enzyme smell. I have blown up the image you sent me and I do not believe that his injuries are from fighting. The fact that the problem is on three locations indicates that he was standing on something when this happened, most likely a high power electric cable. The injury looks like a burn. There may be some dislocation of bones as he fell. I am sure the vet will look for that. Typically recovery from electric shock for howlers is a slow process. But the good news is that recovery is usually complete providing the liver is not damaged.. I have had experience of this with a female in a local town.
O.k take a look at my posting on the blog for the 14th of October 2009. You will find some remarks and a photograph of a young female. Name is Marie Teresa. You see your problem is not a new one. People are often confused by the female external organs. Even local villagers here get it wrong.
I have taken new photographs this morning and I hope this will clarify for you. I think you can be forgiven for not being sure.
The female's name is Emma and she is five years old and she is on heat.

Keep me in the loop on this one. Build him a big enclosure if possible including a live tree. Make a box for his house and cover the door with a sack. He will appreciate a cushion or pillow inside. Please plan on keeping him for at least 6 months.


If you need information on feeding him, let me know.

again God bless you for caring for this little one.
Philip at Canaote

Hi Karen,
You would not consider allowing him to join your family? Maybe he will grow on you. I love the picture you have sent me. He is very handsome. Could be a little younger than I first supposed but he is at least 3 years. Funny seeing a black howler because all ours are red. We live in monkey country and we are surrounded by about 20 troops of howlers. There are also capuchin monkeys in the forest. We do not release ours even though like yourselves, we are on the edge of fairly deep forest, because of zoonotic considerations. Most of our children have come from homes in Caracas and Valencia. They will not have resistance to forest diseases and may transfer human diseases to the animals of the forest. That is of course a very brief explanation.

Make his enclosure as high and big as you can afford. Try letting him loose in the house with the doors and windows closed. He will join you for dinner.
A useful indication of his mood. When they are angry or defensive they puff up to nearly twice their size. The hair stands literally on end.
He will never attack you if you treat him with respect.

Please keep in touch.

Philip at Canaote