living with uninvited non-humans

D works for a pesticide company and tells interesting stories about pesticide use and the relationship between humans and wildlife. I met D when the sounds and smells of rats in the roof became too much to bear. 

D explained that the poison used to kill rats is the drug Warfarin. Warfarin is a drug used in medicine to thin patients' blood to help avoid stroke. Bleeding internally, the rats die a slow and agonizing death. But this is thought preferable to using a fast acting poison because the rats go elsewhere to die and rot. There's not much sympathy for wild rats among humans. 

D doesn't mind too much about killing rats, but sometimes he doesn't feel good about his work.  A woman recently called in a panic because she saw a Gecko in the garden. In this case D was happy he couldn't kill it because it's a species protected by law. But he has to do his job when he gets requested to kill spiders - even if he is asked to spray the garden near the house.

Marbled Gecko Christinus marmoratus found in my garden

He often gets asked to kill Whitetail spiders. These species, and Daddy Long Legs, are impervious to the residual effect of the chemicals. Spraying only kills those there at the time. Others will come in later and be unharmed. So spraying is not really a solution, but people are so scared of Whitetails they want to spray anyway. The toxic chemicals work efficiently with Black House Spiders and Wolf Spiders, species that eat Whitetails. Result: an increase in the Whitetail population, and more money for the pesticide companies.

These common spiders often wander into houses and are venomous - except for Daddy Long Legs, that are harmless to humans. So I can understand the fear, to an extent. Whitetail  bites have been said to cause the skin to break down, like gangrene, but this has not been proven.

Daddy Long Legs that lives in my house

Sometimes you don't see the actual creatures living in the garden. You just know they've been there because of poo droppings, or you might find a dead body. In this case, I found a well preserved skeleton, with bleached bones and prominent orange teeth. 

I identified the bones as belonging to a rodent, probably one of the unfortunate rats that died of internal haemorrhage. I didn't know that rats had orange teeth. It is the result of a yellow-orange iron-based pigment in the enamel layer of their incisors. These incisors continue to grow throughout the animal's life. Their size and shape is maintained by gnawing and grinding the teeth together.  Rats mainly eat seeds, grains and tubers, and live in the garden or the roof. Unlike mice, you don't find them in your kitchen. Rats and mice are closely related, the main difference being size. Rats are bigger.

Some people have pet rats. These are considered good rats, unlike the wild ones. If the pets get dental problems, people take them to see a vet. Rabbit and rodent dentistry is an emerging field of study and practice, but it is still at an early stage of development.

Rats can carry pathogens that cause scary infectious diseases. Like other invasive species, they are never going to be eradicated. Maybe we should consider them as a source of food. Rats are eaten regularly in some parts of the world, and provide a source of protein when there is a shortage of food. A friend of mine grew up in a refugee camp and tells me me they are delicious.