"A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates." - "Many mammals such as dogs, rabbits and moose (elk) possess dewlaps." - Wikipedia
"The dewlap is found mainly on female rabbits, although, in certain breeds, the males are also allowed a small one. Its purpose is to provide another area for the doe to pull fur from when she is making her nest for her kits" - Wiki Answers
"Does in heat may barber their own fur and pregnant does that are close to giving birth may pull hair from the forelegs, the dewlap, lower part of the chest and hips to build a nest." - ExoticPetVet.net
According to the ARBA if your rabbit had a dewlap and was one of the following breeds: Polish, Netherland Dwarf, Tan, Himalayan, Silver, Britannia Petite and Dwarf Hotot they would be disqualified from a show.
Will be less pronounced on a female that has been spayed at an early age
Some male rabbits neutered before full puberty can have more estrogen than a neutered rabbit causing a dewlap to grow
Male rabbits having been neutered after puberty will have a less of a chance getting a dewlop
Some breeds (Like lops, flemish, ....) can develop a dewlop easier that other breeds
Certain breeds that have looser skin will be prone to bigger dewlaps --Lops, Flemish and Giant Chins have a tendency to get the massive dewlaps
Most female rabbits have one, the more overweight the rabbit the bigger the dewlap - overweight males sometimes get one too
"The dewlap usually only develops in overweight rabbits, however the dewlap can persist after weight loss" - Source
Dewlap Talk (Questions asked by 'Carolyn' on the subject @ Rabbits Online)
"There are actually proteins that control the elasticity of the skin. A number of diseases are associated with this protein, but in the case of dewlaps, it appears to be a harmless mutation that doesn't affect other body systems. It would be helpful when researching for info to find info on that particular protein and also on mapped mouse gene mutations of this protein." --- "Also, mutations of this protein are inherited in a number of different ways. Some of the mutationsare recessive, some dominant, some X linked, etc. Of course, only a small portion of them have actually been identified so I doubt that anyone will beable to come up with any more specific info. on the exact mutation that causes loss of elasticity specific to the neck area, that also does not affect another body system. At least one has been identified that causes the skin to loosen, but it is linked to pulmonary disease also. On final edit (LOhL) A geneticist who specializes in that particular protein would be your best best. Yes -- diet is a contributing factor." Source.
"They're mostly due to over indulgence in groceries but may be some genetics. Some breeds don't fault for one in either sex, some just in does and some fault for it in both sexes. Basically a sign of matronly doe but sometimes seen even in juniors in some breeds." - Rick Stahl
The following comes from a conversation Kathy Smith had with one of her Rabbit Guru's and she thought it worth noting: "Mostly larger breeds like New Zealands get dewlaps and generally get them about the time they hit sexual maturity. Also have seen quite afew mini lops, especially larger ones, with them. -- Assuming it is linked to a "strain" within breeds since I would estimate that more New Zealands, Californians, etc., don't have dewlaps than do. It doesn't seem "completely" correlated with age or spay, whether a female has a bad litter, nutrition as a youngster, or over all weight. -- Have seen many fat representatives of larger breeds with no dewlaps as have seen occasional Netherland Dwarfs with tiny dewlaps. -- A case can be made that dewlaps are caused by some kind of X-linked recessive gene, perhaps develop fully only with the presence of proper nutrition in early life, more likely to develop if rabbit is spayed late - and will shrink when rabbit loses weight." - Kathy Smith
"I think the female dewlaps are more like little pockets of weight under the chin rather than the whole chest like an overweight rabbit might have. Even with my more weightier females, it still is a little pocket right underneath their chin. Three of my larger rabbits and midsize females (NZ/CA and Rex) all have dewlaps, but my Harlequin and my other two female mixes, who are also large, do not." - Kathy Smith
Rabbit Tummy Tuck "PSA: Don't let your bunny get overweight!"
This is Roberto recovering from his tummy tuck. He was overweight and then went on a diet. Once he was at an appropriate weight "he had a flap of skin after weight loss that hung over his penis, causing him to pee (and poo) all over his underside which resulted in lots of infections and trouble."
"We had already gotten Roberto back down to an appropriate weight, but all that extra skin and fat stayed in a bad place. We were going to the vet every few months for infections and even on a good day, it was a bad sight down there." - "The vet took a huge pinch of skin and a bunch of fat during the surgery."
40 stitches and $600 later Roberto "seems delighted to be able to properly groom himself again". Thanks to Roberto's mom, SuzanneS for the use of the picture and Roberto's story.
"The top photo above (black and white female) shows a rabbit that was seriously overweight in the recent past and although she lost a lot of the excess weight, the size of the dewlap did not reduce and she needed a dewlap reduction operation which was carried out by the vet to resolve the problem." - reference: Cottontails Rescue
"Grooming your bunny regularly should help prevent problems from occurring, but in extreme cases your bunny may need to be put on a diet or have surgery to reduce the size of the dewlap." - reference: Paw Nation
Dewlap Reduction cost? About $150USD in 2007
Emily (aka Ivory) on rabbitsonline.net posted back in October 2007 about Pellette, needing the reduction operation because of health reasons. Her father (a vet) did the operation and made the remark: "But for 'any other Joe Blow who wants it' (as he put it) it would cost about $150." Done while she was getting a spay. - reference ; full post
Picture of Pellette about 3 days after her reduction operation. Adjusted for inflation in 2019, the cost would be about $187USD.
Dewlap Slowly Getting Bigger question from July 14th, 2014 on allexperts.com. Answered by Dana M. Krempels, Ph.D. (of HRS & H.A.R.E.).
"Some bunnies, no matter how lean, develop real "skirty" dewlaps. No clear reason except genetics, I suppose. -- But do keep checking for anything granular or hard. If there are abscesses within the dewlap, the chronic infection can cause organ problems (liver and kidney). And if there is a tumor, then it should be excised. -- If the dewlap is actually getting in her way, then dewlap reduction surgery is an option you might discuss with your rabbit-savvy vet." - source
The Dewlap - New bunny owners may be a little bit confused about the extra flap of skin and fatty tissue that is under the chin of their new female bunny. This section of skin is called a dewlap. Male bunnies may also appear to have a dewlap, but it is rarely as pronounced as the dewlap on a female.
Dewlap Purpose - The dewlap tends to appear when female rabbits have reached the age when they can begin to reproduce. The dewlap provides a place where the female bunny can pull out her own fur and use it to line her nest. The nest is where she will sleep as well as produce and raise her offspring.
Hair Pulling - It is perfectly normal to see a female bunny pulling hair from her dewlap when she is nesting. With that said, your bunny should not pull all the hair out of her dewlap or do significant damage to the skin underneath. If this behavior occurs, then you need to take your bunny to the veterinarian.
Health Concerns - If a bunny becomes overweight or has a very large dewlap, she may have difficulty eating and grooming herself. Infections can also develop if bacteria or debris become trapped between the folds of the dewlap. Grooming your bunny regularly should help prevent problems from occurring, but in extreme cases your bunny may need to be put on a diet or have surgery to reduce the size of the dewlap. Speak to your veterinarian about any health concerns you have related to your bunny's dewlap.
"Wet Dewlap (Moist Dermatitis) -
Female rabbits have a heavy fold of skin on the front of the neck called a dewlap. As the rabbit drinks, this skin may become wet and soggy, which leads to inflammation. Possible causes include open water crocks and damp bedding. Dental malocclusion that causes excessive salivation can also be a cause. The hair may fall out, and the area may become infected or infested with fly larvae (maggots). The area often turns green if infected with Pseudomonas bacteria. If the area becomes infected, the hair should be clipped and antiseptic dusting powder applied. In severe cases, antibiotics injected by a veterinarian may be necessary.
Automatic watering systems with drinking valves generally prevent wet dewlaps. If open water receptacles are used, they should have small openings or be elevated."