There are two types of rat commonly found in the UK, one being the Brown Rat and the other the Black Rat. They look and behave quite similar, however there are differences.
Black Rat
Appearance
The Brown Rat grows up to 24cm in length and has a longer tail than the length of the body (including head).
The Black Rat has a slender body in comparison to the Brown Rat and has a pointed nose and large ears.
The weight of a fully grown Brown Rat will be between 150g and 200g.
Life Cycle
The average lifespan of a Black Rat is 12 months in the wild.
They produce between 5-10 young per litter and roughly have 3 to 6 litters per year- the gestation period is, on average, 3 weeks.
It only takes 12-16 weeks from birth for a Black Rat to reach sexual maturity.
Habits
Black Rats are great climbers due to being very agile.
Unlikely other rodents, Black Rats tend very rarely burrow and are not often found outside in the UK.
Their preferred food is moist fruit and will roughly eat 15g of food per day – they will roughly drink 15ml of water per day.
Brown Rat
Appearance
The Brown Rat grows up to 40cm in length and has a shorter tail than the length of the body (including head).
They are a lot larger than the Black Rat, the average weight of a Brown Rat is 350–500g.
The body of a Brown Rat is a lot thicker than the Black Rat and it has a blunt nose and small ears.
Life Cycle
The average lifespan of a Brown Rat is 2 years in the wild.
The Brown Rat has 7-8 young per litter and between 3 and 6 litter per year.
Like the Black Rat the gestation period is 3 weeks and they only take 10-12 weeks from birth to reach sexual maturity.
Habits
The Brown Rat’s preffered food is grains and cereals, however, they are omnivorous.
They are the only species to occur in sewers in the UK.
The Brown Rat eats and drinks a lot more than the Black Rat, eating around 30g of food and drinking 60ml of water per day.