Since you’re here, I assume you’re looking to learn about how big do ferrets get? Whether you need to know so that you can pick a cage for your new ferret baby, or you’re curious, we can help you out.
We have the long answer below, in the growth rate section, but it should be mentioned right away, that sometimes it depends.
Sometimes, we’re talking about the age difference between two ferrets. Other times, it’s the considerable male vs female difference that’s to blame. And in some cases, it might be the difference between a whippet and a bulldog variant, since there is more than one type of ferret.
How Big Do Full Grown Ferrets Get?
Hobs, or the male ferrets, will have an average length of 15 inches (38 cm), weighing between 1.5 and 4.4 pounds (0.7 to 2 kg). On average, it’s about 50% bigger than the female.
Jills, the female ferrets, have an average length of 13.5 inches (35 cm), with a weight between 1.3 and 2.2 pounds (0.6 to 1 kg).
How big is the biggest ferret?
Though the typical ferret will go up to 4.4 pounds, finding some that reach 6 pounds is not unusual. Especially true for male bull ferrets, which are more common in Europe.
One thing that can impact a ferret’s growth rate is the age at which it was neutered. If they are neutered while they’re growing, then they will be smaller than those that are at their adult size. There are extra hormones available for them while they grow, which would explain it.
Another element that can help the ferret grow bigger, is having access to raw meat/whole carcasses of prey. Feeding a baby ferret the wrong type of food certainly doesn’t help.
A big ferret might also simply be overweight. In fact, Guiness World Records will not take applications for such a record. The reason is that it might encourage some people to overfeed their ferrets.
While an official record does not exist, the photo below has appeared online of a very large ferret. It’s not clear if it’s real or photoshopped, as no other details emerged.
What’s the ferret’s growth rate like? Males vs females (0-4 months)
You will find that the ferret is a fast grower, and that it takes them a couple of months to reach their mature weight.
Newborn Ferrets: both the male and the female are somewhere around 10 grams (0.35 oz).
In the first couple of days, they have a peach fuzz on their bodies. They need help from their mother to survive, as they’re helpless. They’re blind for the first 5-6 weeks of their lives.
1 week: they quickly grow in size, up to 30 grams (1.05 oz).
2 weeks: again, their size increases, reaching somewhere around 60-70 grams (2.1-2.5 oz).
3 weeks: average weight is somewhere around 75 to 95 grams (2.65-3.35 oz) for females and 100 grams (3.52 oz) for males. A difference between the two sexes starts to appear.
1 month: the female is anywhere between 100 and 150 grams (3.52-5.3 oz), while the male is between 125 and 200 grams (4.4-7 oz).
They start to become curious, and though still blind, they begin investigating the surrounding area.
1.5 months: at this point, they have a length of 12 inches/30 cm (without the tail). The weight is 180-200 grams (0.4-0.45 pounds) for females and 230-250 grams (0.50-0.55 pounds) for males.
At this point, they’ve opened their eyes and they’re going to be curious to see what’s nearby.
2 months: once again, it doubles in weight in a couple of weeks. Females are at 300 to 500 grams (0.66-1.1 pounds), while males are between 400 and 500 grams (0.88-1.1 pounds).
The ferret’s teeth have reached their adult size at 8 weeks/2 months.
4 months: this is their adult size, and on average a female has 13.5 inches (35 cm) and 0.6 to 1 kg (1.3-2.2 pounds). The male has 15 inches (38 cm) and a weight between 1 kg and 2 kg (2.2-4.4 pounds).
Winter vs Summer Weight
Another element which could explain a ferret’s weight increase, is the change of the seasons.
Bulking up is a process that takes place in the first couple of years of the ferrets life, where he takes on weight for winter. He then proceeds to lose weight as summer comes near.
The difference in weight can be huge, to the point where the ferret is overweight. The weight can be up to 40% more during winter months, compared with summer ones.
As it advances in age, there is less of a difference in size over the year.