Rats as big as cats in the UK! Rat catching cats don't stand a chance.

To those of us living in the UK we are seeing more headlines about rats getting larger. They say they are as big as cats. If it's true there is little prospect of domestic cats being usefully employed as rat deterrents. Today's domestic cat ratter will just run away from these monsters.

Massive rat as big as a cat. Image by MikeB based on an image in the public domain.

But in general, I think they are mythical. People like to believe that they are very large. It adds to their story of woe. But if they are larger, it must be an evolutionary process over a very long time.

Animals may evolve to be larger over time as a result of natural selection. Larger individuals may have advantages in terms of survival and reproduction. For example, larger animals may be better able to defend themselves against predators, compete for resources, or attract mates. Additionally, larger size can confer other benefits, such as the ability to travel further or withstand harsh environmental conditions.

However, it's important to note that evolution is not always directional, and animals can also evolve to become smaller or stay the same size over time, depending on the specific environmental pressures they face. Furthermore, evolution is a slow process that occurs over many generations, and there are many factors that can influence the size of a species, such as the availability of resources, predation pressure, and climate change.

AI says this about rats getting larger

There have been reports in the media suggesting that rats in the UK are getting larger, but the evidence for this is mixed and controversial.

Some studies have suggested that rats in urban areas may be increasing in size due to factors such as access to more food and reduced predation pressure. However, other studies have found no evidence of size increase and suggest that the average size of rats in the UK has remained relatively constant over time.

It's important to note that size variation in rats can also be influenced by a number of other factors, including genetics, environmental conditions, and disease. Additionally, different rat populations may exhibit different size trends depending on their location and specific ecological conditions.

Overall, while there may be some evidence to suggest that rats in certain areas of the UK are getting larger, it's difficult to make generalizations about the entire population without more comprehensive data.

Cold climates

Normally animals of the same species living in cold climates are larger such as the puma in North America compared to the same species in South America.

The same difference applies to the tiger. The Siberian is larger than Bengal. The Sumatran is the smallest. Evolution ensures that the bigger animals can keep warmer because of an improved mass to surface area ratio.

This is supported by prey animals also being smaller in warmer climates which feeds into the evolutionary process ensuring that predators such as the tiger is smaller too.

On that basis rats in the UK may be getting bigger to keep warmer as it enhances survival and the evolutionary process is supported by the presence of abundant food supplies because of an increased human population in the UK.

Ratters

The old idea that domestic cats are good at deterring and killing rats hardly applies today. Domestic cats are not great rat catchers. They can be intimidated by a big rat. 

They don't want to risk being injured so leave it alone. It depends on the individual cat. They may even run away from a marauding rat. Rats can be very aggressive and courageous. They are good predators themselves. They've been involved in the extinction of some species on islands.

GB's greatest rat catcher

The UK's greatest rat catching cat was a female living in and around the now non-existent White City Stadium. She is said to have killed no fewer than 12,480 rats in her life. A daily average of 5-6.

A formidable achievement which reflects the reason why the wildcat was domesticated in the first place around 10k years ago. They were utilitarian, working cats as well as companions.

Companions now

Domestic cats nowadays are almost exclusively companions and entertainers to their caregivers.