Although we love our pets, specially dogs and cats, we cannot forget that they came from predator ancestors, who use to hunt in pacts in the case of dogs or alone in the case of cats. Therefore, they still have in their genes that instinct to hunt even if we tamed.
Today post we are going to talk about domestic dogs and cats effects at the study area. In past months there was an article about the effect of domestic cats on Australian fauna and the results were just terrible for wildlife, from birds, lizards, frogs and small mammals. Although there is not that kind of information for Colombia, for sure there is an effect on domestic dogs and cats.
At the study site, the effects on the wildlife are not clear. There is dogs and cats at every farm and palm oil plantation in the study area. They move around freely and through all farms without any restrictions. Around houses cats hunt small birds, preying on nest and small birds learning to fly, small rodents and rats.
At the forest fragments, live fences and wire fences dogs attacks monkeys, tamanduas, coatis and other mammals. At cattle pastures dogs also attacks giant ant eaters and sometimes other domestic animals, like goats.
Over the past 16 years, we have witness at least two confirmed successful dog attacks, both on black-capped capuchins (Sapajus apella). At least three more unsuccessful attempts were witness on Colombian squirrel monkeys (Saimiri cassiquiarensis albigena). There has been local people reports on dog attacks on red howler monkeys, especially when they move on the ground through pastures from one fragment to another.
In the past two years local workers from one of the farms with which we work reported a group of at least four dogs from a near palm oil plantation hunting in the forest fragment where we have been monitoring monkeys for more than a decade.
Although we will need a more detailed information of how domestic dogs are affecting the wildlife in the area, at least we know the presence and probably the freedom with which we are handling our domestic dogs and cats is affecting the wildlife living in highly fragmented areas.
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Today’s post I’m going to explore a question a colleague makes to me a few days before I went to the field, ¿Are you scare when you work at night? But first, let’s explain why sometimes we have to work at night.

As you have notice from this website, at the study area there is nocturnal species, Brumback’s night monkey, a small size monkey who make all its activities during the night. They sleep during the day in hollow trees or very high trees cover with lots of lianas and vines and they search for food and move around during the night.

To be able to know how they live, how many they are and in which forest fragments we can find them, sometimes we need to go out at night and search for them. Although we have not been so successful as in other places to follow them at night, we have been able to count them and find out some of the forest fragments in which they live in the study area.

My first nocturnal monkey counts weren’t in the study area, they were in the Amazon, in large areas of continuous forest, where there is also big wild cat such as cougars and jaguars around at night. So, in those days, specially at the beginning yes, I usually was scare while doing my work at night. I was always with an indigenous who knows the forest a lot and who was good at recognizing many animal sounds and smells.

At night, you can rely on your vision as much as you do during the day so you learn to recognize the sounds of nocturnal animals, and sometimes the sounds of some diurnal animals that you encounter sleeping during night walks. For example, during this last fieldwork we were working in one of the fragments in the study area, one that I never walked before at night, and we found a small group of coatis sleeping in a high tree, near to the stream. I had never encounter them at night before and never paid attention to the noises they do, so at the beginning it was difficult to know what they were, we just saw small bright green eyes, until we can use our binoculars and see their long nose and fluffy banded tail.

At the study area, usually is not that scary to work at night as it was in the Amazon, because the forest are smaller and I have walk them for so many years I can recognize parts of some of those forest fragments even with poor light. My main concern in the study area is to meet a person during night work, that is why we usually do night work only in farms where we make sure the landowners and farm workers know that we are there.

We sometimes found snakes that usually leave you a bit shaken, but don’t attack you. In the bigger forest fragments in the area sometimes we hear or found tracks of jaguar or cougar but never met them face to face. Not in this area, although I met the in the Amazon and in Macarena (a bit southern from the study area)…

So, the answer to my colleague’s question is yes and no, depending on where I’m working at night…

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In past days when talking with local people, from farm workers to landowners, we were asked several times why we are counting the monkeys year after year? What is the purpose of that? In today’s post, we are going to answer these questions.
Like us monkeys live for several decades, therefore like us every year there are many events happening in their lives, there are some babies born, some old animals die, some accidents can happens that kill some individuals, there are also some disease that also kill or make some individuals more prone to be kill or eaten by other animals.
So when we visit a forest fragment to count individuals, we register every event and observation that can indicate the health state of an individual. We also register every individual we found, their sex and approximated age. All data collected during a year is used to compare it with previous years data and that information give us information about how the population is in each fragment.
As the monkeys in the study area lives for more than 30 years, if we only visit the fragments one year we cannot say much about how the population is doing, we need to sample for more than one decade to know what is happening.
For example, thanks to the sampling we have done since 2004, we know the deaths of some males of Colombian squirrel and red howler monkeys in the area. We also have learned that some old females of Colombian squirrel monkeys seems to stop reproducing after certain age.
This information also help us now that for now the population of all the species we have been monitoring since 2004 in the study area is stable and not decrease despite the habitat fragmentation present in the area. However, 16 years is still not so long time if we have in mind that monkeys species in the study area lives around 30 years or more. So we still need to continue monitoring these populations for at least two more decades…
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On some past post I have talk about where monkeys move, but we have not talked about how they move and by this we mean if they are quadrupedal (i.e. move like dogs and cats) or bipedal (i.e. move like us), or they move leaping (i.e. jumping from tree to tree) or by using the suspensory behavior (i.e. climbing a tree).
Well, primates in general use all these forms of locomotion (movement) and some species use one or more of these locomotion forms during their lives depending on their activities. For example, quadrupedal locomotion is used by monkeys in two forms: arboreal quadrupedal movement, when they walk on their four limbs on big trees branches and terrestrial quadrupedal locomotion when they walk on their four limbs on the ground in search of food. Some used both forms of quadrupedal movements because they use both trees and the ground during their search for food and other activities.
In the study area, black-capped capuchins and Colombian squirrel monkeys use all forms of locomotion depending on the activities they are doing (see video, below). For example, when foraging for insects and spiders on the ground they use terrestrial quadrupedal movements, but they also can move bipedal for a couple of minutes if they are carrying some heavy fruits with their hands or to have a better look on the ground in search of insects. They both also use leaping to move between trees and even some times they use the suspensory behavior to climb to the top of big trees or to be able to cross gaps between tree tops that there are not so far apart.
Red howler monkeys are masters on the use of suspensory behavior to reach flowers on the thinner branches of some trees or to reach fruits from trees that may not support their weight to they use their body weight on stronger branches to reach those fruits. They also move using arboreal quadrupedalism on big trees with wide branches and sometime leap between branches during their long-distance movements.
Dusky titi monkeys and Brumback night monkeys use more arboreal quadrupedalism and leaping on their movements in search of fruits and when moving fast on the forest canopy. Dusky titi monkeys sometimes also use terrestrial quadrupedal movement when searching for insects on the ground. We didn’t see Brumback night monkeys on the ground yet, but they use leaping and fast arboreal quadrupedalism to avoid us as much as they can.
How monkeys move is an important part of how we describe what monkeys do during their activities and it explain some modifications in primates’ bodies as well as particular behaviors.
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