A recent study carried out by researchers at the University of Alabama (USA) showed that being overweight doesn't just affect people . Companion and laboratory animals also suffer from this problem, which has been on the rise for the past 60 years. To reach this conclusion, the scientists compared the weight variation of various species from 1948 to 2005. The results show that laboratory animals such as rats suffered a 10 percent increase in their body mass, the same as companion animals like dogs and cats. On the other hand, species of primates in laboratories, such as chimpanzees, gained as much as 30 percent for every decade that passed.
Although overfeeding may be a reason in the case of companion animals, what the laboratory animals eat has remained practically the same throughout this time. David Allison, co-author of the study that was published in the journal Proceedings of the Royal Society B , suggests that it could be due to certain substances that alter the metabolism and endocrine system of animals , or to viruses such as adenovirus-36 , which are has shown that in certain cases it is linked to obesity. An increase in temperatures in the rooms where these animals live could also explain the weight gain, according to Allison.
