Obesity has been one of the most important risk factors of the ever-increasing mortality rate in humans associated with a few life-threatening diseases usually grouped according to its respective major system; cardiovascular system, respiratory system, nervous system etc. We know what causes obesity in humans and theoretically if we can make sense every aspect of pathophysiological characteristic of human diseases with animals, we can relate and predict what is going to happen if let say, an animal is obese. The problem is every single animal behave in a different way, for example, a lion can eat for 24 hours and go without eating for a week; with that kind of behaviour it's impossible for them to become obese but it would be different if they were raised in captivity.
It is important to note that, when an animal is living in the wild, they would hunt for food whenever they got hungry. It's like the Native Americans before the European settlers came into their respective lands. In a book written by Abigail Caroll, entitled Three Squares, The Invention Of The American Meal, Native Americans were illustrated as being uncivilised by the European settlers as one of the reasons being, native people would be eating whenever they felt hungry. They have never allocated any time specifying when they should eat until the time when the European settlers introduced the concept of eating in the morning (breakfast), noon (lunch) and evening/night (dinner); those routine have been programmed deep inside of our body system making our stomach started to churn when the clock said "It's time to eat".
I've never seen a relatively obese animal (compared by using their baseline weight as a reference value) living in the wild but I've often seen obese pets living in someone else homes. It is a kind of problem which should be taken seriously because just like obesity in humans, animal's obesity is one of the key predictors of longevity. A paper which has been published in 2002 by Kealy et al, which has been focusing on the relationship between animal's lifespan and diet, has found that a 25% reduction in the total pet dogs daily caloric intake can extend the median lifespan (it is an age point whereby 50% of the dogs in a population died) by significant figures while improving their quality of life (measured by the presence of chronic illnesses as a result of the diet intake).
~ Professor of Physics, Michio Kaku
It's quite difficult to determine what is the upper and lower boundaries of a normal weight for different species of animals. When we are being provided with a random number which should represent a minimum and maximum of the lower and upper boundaries of an animal's weight as a reference, the figure, in theory, shouldn't be universal; for some animals, it can be normal, for others it can be overweight or even underweight. We are not going to use the same parameter when we are comparing the rate of obesity among different kinds of animals like horses and hippos. Comparing, relating and try to come up with a range of acceptable figures to determine if an animal is obese is an arduous task and seems irrelevant when we compared their usefulness with the cost incurred.
It's one of the reasons why most of the obesity studies were conducted among pet animals. Unlike any other wild animals, pet animals are much more likeable and cooperative making it easier and cheaper to conduct tests. However, even if the physiological processes and the pathophysiological consequences of obesity can be thought as the same as the rest of animals in the animal kingdom, the concept might not be that accurate as different animals have a different rate of metabolism (and sometimes with different body mechanics) to explain why some animals were prone to obesity in captivity while others are not.
Does An Animal Overeat While Living In The Wild?
Nature has been managing that pretty well. Let's take a cheetah as an example. For a cheetah to thrive, they need to be able to catch their natural prey which is usually gazelles or antelopes. Gazelles might be slower than a cheetah and even though a cheetah can run at 120 km/h, top speed, their success rate was below 50%. This is due to the fact that a cheetah wouldn't be able to deal with a hard turn made by its prey while in its top speed. Lower catch rates equal to lower food source which has been one of the key components that were controlling the rate of obesity among the animals that were living in the wild.
For the sake of argument, let's say, one day, a single cheetah was able to eat 4-5 prey which later, making it obese. Theoretically speaking, it can't run as fast as a gazelle or an antelope anymore which will make it harder for them to catch their own prey. This will lead to a variable period of starvation, making them thin again as a result of caloric deficits. As a predator who relies heavily on their speed, obesity is a major concern. Have you ever went to a Zoo? Try to compare the condition of the animals which were raised in the Zoo setting with the one which is being raised in an open Safari. Which one do you think would be much healthier, physically?
In the Zoo, sometimes, animals are overfed for the sake of performances, they were eating 3-4 times a day, in which the cumulative caloric intake might have exceeded or just the same with the one which has been living in the open Safari. Sometimes, they were underfed as a result of poor understanding regarding the caloric utilisation of the animals which are usually dormant in the Zoo setting or the Zoo simply ran out of budget or experiencing some budget cut so they were trying to reduce the amount of ration provided to the respective occupants.
Some articles suggested that, in the wild, some animals seem to eat more than it should just because they wanted to copulate with their females species. Yeah, that's right. In the wild, for some animals, caloric utilisation was spent mostly to fertilisation process. There were several factors that would affect the rate of consumption of an animal such as the availability of prey, the specific duration of the time of hunting and last but not least, diseases. A lion can easily engulf a 90 pounds worth of food in a single feeding but usually, the duration between hunting is a week, so it's reasonable to stuff yourself as much nutrient as you could to last for a week (or more). It's quite a relative term, "overeat" if we would like to discuss it in the context of a vast and various community such as the animal kingdom.
Pet Animals Obesity
You might be kind of unfamiliar with pet animals obesity, but if you know the obesity as a general term, then you would know it can cause a lot of problems which might lead to an increase in mortality and morbidity rate. Well, in pets, obesity is on the rise for the few years and most of the preventative measures suggested were half-cooked, it will only affect the animals in the short-term with a poor long-term outcome. In 2014, a study which was conducted by the Association for Pet Obesity Prevention has found that a majority of the dogs (53%) and cats (58%) population which were kept as pets were obese. If we want to compare the success rate of weight-losing programs for humans and for pets, only a small percentage of participants (25-30%) were able to lose and maintain their weight. The rest? Well, they lose a moderate amount of weight on a short-term but regain weight a few months later. Losing weight is difficult regardless it is for humans or animals.
The concept of excessive weight gain among pets is poorly understood but it might be caused by the same problems faced by humans; poor diet, sedentary lifestyle and hormonal imbalance. Some owners were too empathetic with their own pets making it seems justifiable for them to stuff their pets stomach with lots of food or giving them something which can be considered odd or unsuitable for their own pets. Some human's foods have higher calories compared to the one which is usually contained in the standard cat's food. Do you want to guess where do the remaining unused calories going to go? If we combined it with the fact that a house-bound pet was more likely to loaft which signify a reduced in the physical activities, then obesity is a clear, probable outcome.
A pet which has been neutered or spayed by their owner would require a different kind of dietary requirement which is often overlooked by their respective owner due to the lack of knowledge. Animals which have been neutered for population control would have some sort of hormonal imbalance that would slow down their metabolism leading to a low-caloric requirement. However, it is worth noting that, pets that have been neutered are prone to some kind of psychological instability, which can lead to depression and hyperphagia (overeating). Hyperphagia would, of course, extend to the point of obesity (if it is not well-monitored). Consulting a veterinarian would be a wise choice in managing problems, faced by your pets.
References and further reading materials
- Do Animals Overeat in the Wild?. Retrieved on June 10th, 2018.
- Can wild animals become overweight?. Retrieved on June 10th, 2018.
- Why Don’t Wild Animals Get Fat?. Retrieved on June 10th, 2018.
- It's Not Just All Of The People Around You That Are Getting Fatter. Retrieved on June 10th, 2018.
- 8 Shockingly Obese Animals. Retrieved on June 10th, 2018.
- Effects of diet restriction on life span and age-related changes in dogs.. Retrieved on June 10th, 2018.
- Obesity in pets. Retrieved on June 10th, 2018.
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