To cool down from excessive heat, many animals will pant, increase skin blood flow, and in a small percentage of mammal species, sweat. Sweat, that messy, smelly, salty liquid produced by skin glands is not unique only to humans. If so, do monkeys sweat?
Yes, monkeys sweat, just like humans. Some Old World monkey species, like the stump-tailed macaques, snow monkeys, baboons, squirrel monkeys, and patas monkeys, all have sweat glands that allow them to perspire.
Let’s dig deeper into this.
Sweating In Monkeys
Thermoregulation is a process that allows our bodies to maintain the core internal temperature of around 98.6°F (37°C).
When our body temperature becomes higher than that number, the part of our brain that controls temperature, the hypothalamus, will send a message to our body, telling it to sweat. After that happens, the special glands in our skin called sweat glands will start making sweat.
Sweat, or perspiration, is mostly made of water, ammonia, urea, salts, and sugar. The sweat leaves our skin through pores, and when it hits the air, the air makes it evaporate (turn from a liquid to a vapor). As the sweat evaporates from our skin, we cool down.
Besides humans, other primates like the apes and monkeys sweat. They have two types of sweat glands, apocrine and eccrine.
- Eccrine sweat glands – when found on hands and feet, they produce sweat to help with gripping objects; when found on the body surface, they produce sweat to cool down the body
- Apocrine sweat glands – located at the base of hair follicles, they produce odors and other (smelly) secretions that act as pheromones, territorial markers, and warning signals
Most mammals have eccrine pores only in the soles of their feet or hands. When animals feel stressed, i.e. when escaping a predator or catching prey, the salty liquid from eccrine glands will provide extra friction for landing jumps and for climbing.
At some point in evolutionary history, eccrine glands spread from the soles of feet and hands to other body parts. like the torso, face, and limbs.
The Old World monkeys, for example, have eccrine glands over their entire body surfaces and use them for thermoregulatory sweating. Baboons, macaques, and patas monkeys all sweat through their eccrine glands in response to heat.
Eccrine sweating acclimation similar to that in humans has been demonstrated in the Japanese snow monkey and patas monkey.
In fact, a study at the University of Iowa discovered that patas monkeys sweat 2-6 times more than the rhesus monkeys; the patas also have larger eccrine glands than rhesus macaque monkeys.
2 factors affect how much monkeys will sweat: glycogen stores and the number of capillaries. Glycogen fuels sweat production, while capillaries carry the ingredients the glands need to make sweat.
Monkeys that live in hot and dry climates have sweat glands that store more glycogen and have more capillaries.
Do Monkeys Pant To Cool Down?
Panting is a method of cooling where an animal rapidly breathes through its nose and the mouth, expelling hot air and drawing in cooler air. Examples of animals that pant to cool down are cats, dogs, and pigs.
Like dogs, some monkeys may use panting as a way of regulating their body temperature, but only a little since they have an easier way of reducing the heat. They can simply sweat.
Do Gorillas And Other Apes Sweat?
Just like the monkeys, gorillas also have eccrine (sweat) and apocrine glands. They sweat just like humans – their sweat glands closely resemble human ones and their distribution on the body is also similar to that found in people.
Gorillas also have specialized tissue on their armpits called axilla or axillary organ. The tissue consists of 4-6 layers of glands that secrete sweat and different scents.
When it spots enemies near their group, a silverback will produce a strong smell as an alarm signal to other gorillas. Female gorillas, on the other hand, will produce an intense smell when they are ready to mate.
The chimpanzee, another ape, has the same complex of large apocrine glands together with an equal number of eccrine glands in its axilla. They also heavily rely on panting due to not being able to sweat most effectively with their fur-covered skin.
Other Methods Of Cooling In Animals
Animals that do not have sweat glands and do not pant to reduce excessive heat, will use methods like convection, conduction, pooping, evaporative cooling, and behavioral thermoregulation.
Convection – a mechanism where the heat is transferred from the animal by the flow of the fluid surrounding it (air or water, for example).
Conduction – losing heat in contact with a colder surface, lying on the cold ground, staying wet in water, or rolling in the mud. Animals include pigs, buffalos, elephants, etc.
Pooping – some species of storks and vultures will defecate on their legs to cool down; as poop gets dried on their legs, the heat gets reduced.
Evaporative cooling – also known as panting – many lizards will keep their mouths open to cool down.
Behavioral thermoregulation – includes behavioral tactics such as shade-seeking to maintain body temperatures within selected bounds.
Adaptive heterothermy – a process where an animal self-regulates its body temperature under the effect of the environment. For example, a camel will increase its internal body temperature to follow the outside temperature to avoid sweating.
Estivation – a state of dormancy during hot and dry periods where an animal reduces its breathing rate, heart rate, and metabolic rate, and as a result cools down. For example, gorillas do not estivate, but some snails, crocodiles, hedgehogs, tortoises, birds, and reptiles do.
Gular fluttering – the avian version of panting – birds will vibrate their throats to cool down. Birds that resort to it include cormorants, pelicans, boobies, anhingas, frigate-birds, herons, owls, doves, roadrunners, etc.
Read More: Birds That Have Orange Beaks
Final Thoughts – Do Monkeys Sweat?
Love it or hate it, sweating is one of the things that makes primates like humans and monkeys unique. And just like us, monkeys can thermoregulate their body temperature. If the outside temperature increases, they will start sweating through their sweat glands to keep homeostasis. In case sweating isn’t effective enough, they might look for shade, or start panting.
Scientists discovered that monkeys living in hot and dry areas have high-capacity sweat glands. But besides these primates, other animals like horses and hippos sweat as well.
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