Dingo became bigger once against them began using the poison 1080 in the second half of the twentieth century. To such conclusion scientists, 559 comparing the skulls of wild dogs in four regions of Western and Central Australia. They calculated that the Dingo on average, added about a kilo after the start of a campaign to control their population with poison. This may be due to selection that favored survival of larger individuals, or in reducing competition between young individuals. As noted in an article for the journal Biological Journal of the Linnean Society, is one of the first examples of the use of poisons alters the phenotype of large vertebrates.
People often use different poisons to control animal populations that are considered pests. However, sometimes this practice leads to unintended consequences. For example, in response to the widespread use of pesticides invertebrates often develop resistance to them, and in some cases, the changes affect even their anatomy.
The influence of anthropogenic toxins on the evolution of large vertebrates is studied much worse. In an attempt to understand this issue Michael Letnik (Michael Letnic) from the University of New South Wales and Matthew Krauser (Mathew Crowther) from the University of Sydney drew attention to the Dingo (Canis lupus dingo). Although many dingoes is the symbol of the Australian nature, like the kangaroo and Koala, the local farmers see them as a threat to livestock. To help control the population of wild dogs, they use poisons, primarily sodium fluoroacetate, commonly called 1080. They are stuffed with meat baits which scatter in the habitats Dingo.
Typically poisoned bait contain enough 1080 to kill a Dingo of any size. However, environmental factors can reduce the concentration of the poison in the piece of meat, so it will be dangerous only for small but not for large individuals. Letnic and Crowther suggested that as a result of dingoes from areas where they are regularly bullied, will gradually increase in size.
To test this hypothesis, the researchers compared the skulls of wild dogs from three arid regions in Central and Western Australia before and after their population began to be controlled using 1080 (in the years 1960-1970). As a control used the skull dingoes from the area where they are never hunted.
After analyzing 559 samples, Letnic and Crowther came to the conclusion that the skulls of dingoes increased by 3-5 millimeters in all three regions where they used 1080. Changes have occurred in just a few decades after the beginning of the use of poisons. At the same time, where wild dogs are not persecuted, their skulls have remained the same.
The length of the skull reflects the overall size of the dog, from which we can conclude that the use of 1080 Dingo did more. These results and expect to see the researchers. However, contrary to their initial hypothesis, in two of the three regions has increased not only females but also males Dingo (as the latter are larger than females, they were considered less vulnerable to poisons). On average, males gained 0.86 kg, and females of 1.02 kg. As soon as Dingo become bigger, in every poisoned bait, you need to add more poison.
The authors acknowledge that selection for large size is not the only possible explanation for why the dingoes become more. Under the alternative hypothesis, the death of a large number of young individuals from the venom reduces competition between the survivors and allows them to grow faster and become larger.
Several years ago, Australian archaeologists have found some evidence that the Dingo was used for hunting by primitive natives. Rather, they helped women to collect small animals. Previously it was thought that the Dingo ever was as a hunting dog.
Sergey Knee High