Dewlap: The Rabbit Double Chin

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What gives some rabbits the adorable double chin look? That floppy flap of skin hanging from the neck that wobbles as they hop is actually a distinct anatomical feature called the dewlap. While many domestic rabbits sport this signature skin fold, dewlaps come in all shapes and sizes. From tiny ruffles to massive drapes of furry fat, the dewlap is a key aspect of rabbit appearance. But why do rabbits have dewlaps at all? Are dewlaps strictly for decorative purposes or do they serve a function? Whether prominent or negligible, dewlaps are a bunny staple. Read on to learn all about the wonders of the rabbit dewlap – the mark of a true lapine aristocrat!

The characteristics of a dewlap

A dewlap is the fold of loose skin that hangs from the neck of some rabbits, resembling a double chin. It is located on the ventral surface of the neck, extending from the jawline to the chest. The dewlap is composed of skin and fatty tissue, making it soft and pliable. When at rest, it may appear simply as loose neck skin, but when the rabbit lowers its head, the dewlap becomes more pronounced as it droops and folds. The size of the dewlap can vary considerably between individual rabbits, ranging from barely noticeable to very large and floppy. Typically, the larger the breed, the bigger the potential dewlap. Lop-eared breeds in particular tend to have more substantial dewlaps. The dewlap is covered in fine fur, though the skin beneath may be lightly pigmented. The dewlap serves no known biological function, though some speculate it may help regulate body temperature. Overall, the dewlap is a characteristic feature of domestic rabbits that adds to their endearing appearance.

Why do rabbits have dewlaps?

There are several theories as to why rabbits have dewlaps:

  1. Temperature regulation – The dewlap may help rabbits regulate their body temperature. When hot, rabbits can engorge the blood vessels in the dewlap to release heat. When cold, they can constrict the blood vessels to conserve heat. The large surface area of the dewlap skin and its exposure to air facilitates heat exchange.

  2. Communication – Rabbits may use their dewlaps to communicate with each other. An engorged dewlap makes a buck appear larger and more impressive to potential mates. Dewlap flashing may also signal aggression or act as a threat display.

  3. Fat storage – The dewlap provides an area to store excess fat. In lean times, this reserve energy can be drawn upon. The relatively hairless skin of the dewlap also allows for efficient transfer of fat.

  4. Evolution from wild rabbits – Wild rabbits may use dewlaps to scrape away fur to line their burrows or to carry nesting material. Domestic rabbits likely retain this anatomical feature from their ancestors even though it no longer serves a purpose.

  5. Breed characteristic – In some breeds, like lops, prominent dewlaps are selected for as part of the breed standard for showing. The dewlap is part of the distinctive look of the breed.

  6. Genetic factor – There appears to be a genetic component associated with dewlap size. Some bloodlines tend to have larger dewlaps than others.

The true reason is still debated, but domestic rabbits continue to possess this skin fold likely due to a combination of the above factors. For pet rabbits, the dewlap simply adds to their cute appeal!

When does a dewlap develop?

A rabbit's dewlap begins to develop as they mature:

  • Baby rabbits – Newborn and juvenile rabbits have little to no dewlap. The skin of the neck is tight with no folds.

  • 6-12 weeks – As rabbits grow out of the baby stage, a small dewlap may start becoming noticeable. Often the first sign is fur growing longer in the neck area.

  • 3-6 months – The dewlap typically grows most prominent when rabbits hit puberty between 3-6 months old. Sex hormones stimulate the accumulation of fat in the neck skin.

  • Larger breeds – Larger rabbit breeds tend to develop dewlaps earlier and with more exaggeration than smaller breeds. A lop-eared bunny may have a significant dewlap by 3-4 months old.

  • Bucks vs does – Male rabbits generally develop larger, more prominent dewlaps than females. The dewlap is thought to be used in establishing dominance and attracting mates.

  • After spay/neuter – Altering rabbits often reduces the size of the dewlap somewhat as sex hormones are reduced. But an existing dewlap will not disappear entirely.

  • Dewlap size fluctuates – The size of a rabbit's dewlap may fluctuate somewhat throughout its life along with weight gain/loss and hormone levels. But the basic extent is established during maturation.

So while a mini Rex may only ever have a small neck ruff, a Flemish giant buck will likely always have a pendulous dewlap fold. The dewlap is a natural part of rabbit development.

Can a rabbit's dewlap be too big?

In most cases, a rabbit's dewlap is perfectly normal and healthy, even if large and floppy. However, sometimes an excessively large dewlap can cause issues:

  • Dermatitis – Excess skin folds harbor moisture and waste. This can lead to skin irritation and infection.

  • Difficulty grooming – An oversized dewlap gets in the way when a rabbit tries to groom itself. Areas may be missed.

  • Heat stress – Big dewlaps provide excessive insulation that may cause rabbits to overheat.

  • Skin injury – Dewlaps can get caught on objects and be torn. The thin skin is fragile.

  • Messy fur – Food, water and waste can soak into the dewlap fur leading to matting and irritation.

  • Discomfort – The weight of an heavy dewlap may place strain on the neck and shoulders.

  • Impaired mobility – In severe cases, a huge dewlap can restrict range of motion and activity.

To determine if a dewlap may be problematically large, look for signs of irritation, soiling, injury or difficulty moving. Discuss any concerns with an exotics vet. If health or hygiene is impacted, surgical trimming of the dewlap may be recommended.

What if my female rabbit doesn't have a dewlap?

It's quite common for female domestic rabbits to have small or nonexistent dewlaps. This is because the dewlap is strongly influenced by sex hormones. Females simply don't produce the testosterone levels that stimulate dewlap growth like males do.

Some reasons a doe may lack a noticeable dewlap include:

  • Genetics – Some breeds and bloodlines are predisposed to smaller dewlaps. Mini Rex and Netherland Dwarf rabbits often have barely discernible neck folds.

  • Age – Young rabbits under 6 months usually have yet to develop a dewlap. Give it time.

  • Spaying – After spay surgery, existing dewlaps often shrink due to reduced estrogen. Does spayed young may never grow one.

  • Pregnancy – Pregnant and nursing does will transfer fat stores from the dewlap to their kits. The dewlap decreases in preparation for kindling.

  • Slight build – Smaller framed, delicately built does tend to have less substantial dewlaps overall.

  • Fur coverage – In long haired breeds, a small dewlap may simply be hidden by the coat. Feel with your hand to detect it.

As long as your doe is healthy and at a good weight, a missing or tiny dewlap is no cause for concern. It is perfectly normal for does. Focus instead on general condition and wellbeing.

Why does my male rabbit have a dewlap?

It's common for male rabbits to develop prominent dewlaps while females of the same breed have very small or nonexistent ones. This difference is due to the influence of testosterone on dewlap growth:

  • Testosterone stimulates subcutaneous fat cell production and enlargement in the neck region, causing the dewlap pouch to become engorged and expand.

  • Males produce high levels of testosterone starting around 3-6 months old, which correlates with when the dewlap first becomes noticeable.

  • Testosterone also increases vascularization and blood flow to the dewlap skin, making the surface swollen and ruddy. This displays breeding condition.

  • Does and altered rabbits with minimal testosterone have less fat accumulation and blood flow in the dewlap area.

  • Intact males tend to display more dominance behaviors involving the dewlap, like flashing during courtship and aggression.

  • Breed standards for bucks often emphasize dewlap size since it is a signal of masculinity.

So while his sister may just have some neck scruff, your buck's hormonally-charged dewlap is completely normal and even desireable! Just keep it clean and monitor for any issues.

Dewlaps in show rabbits

In show rabbits, especially bucks, a large, well-developed dewlap is considered an important asset and is influenced by several factors:

  • Breed standards – Lop and large breeds call for obvious dewlaps as part of an impressive physique. Smaller breeds aim for proportionate dewlaps.

  • Gender – Buck dewlaps should be larger and more pronounced compared to does.

  • Age – Mature adult rabbits past 6 months should have fully emerged dewlaps.

  • Condition – Well-fed show rabbits carry more fat in the dewlap. Judges check for appropriate fill.

  • Grooming – Dewlaps are groomed to emphasis size. Fur may be carded and smoothed into shape.

  • Genetics – Rabbits from lines known for good dewlaps are favored.

  • Hormonal status – Intact bucks have an advantage over altered rabbits for exhibiting large dewlaps.

  • Presentation – Handlers will position the rabbit's head and shoulders to best display the dewlap to judges.

Asymmetrical, wrinkled, ragged, or furless dewlaps are faulted. An ideal show dewlap is smooth, symmetrical, and proportional to the breed. It demonstrates prime condition.

Tips and Tricks

Here are some useful tips for caring for your rabbit's dewlap:

  • Check the dewlap daily and keep it clean and dry. Gently wipe with a damp cloth to remove any urine, feces, or food debris.

  • Examine for signs of skin irritation, infection, or fur loss. Treat any skin issues promptly.

  • Brush the dewlap fur gently using a soft brush to remove loose hair and distribute skin oils.

  • Trim fur around dewlap if it becomes heavily soiled or matted. Do not shave the dewlap.

  • Apply pet-safe anti-mat spray after bathing to help prevent wet fur from clinging together.

  • Avoid fatty treats and unlimited pellets to prevent excessive weight gain and dewlap enlargement.

  • Provide soft bedding and grooming aids to make it easier for rabbits with large dewlaps to reach all areas.

  • Visit your vet if the dewlap seems impacted or infected. Surgery may rarely be needed to reduce an oversized dewlap.

With proper daily care and attention, your rabbit's dewlap can remain healthy and clean. Alert your vet if any unusual changes occur.

Recommended Products and Brands

Here are some recommended products for caring for your rabbit's dewlap:

  • Oxbow Bunny Basics T Diet – High fiber rabbit food promotes healthy weight

  • Small Pet Select Natural Rabbit Chew Toys – Helps wear down growing teeth

  • Kaytee Timothy Hay – Provides roughage and aids dental health

  • Living World Deluxe Grooming Kit – Slicker brush and comb for dewlap grooming

  • Carefresh Natural Paper Bedding – Ultra absorbent and soft bedding

  • Critical Care by Oxbow – Recovery food for convalescing rabbits

  • PETMAKER Polyester Hand Grooming Glove – For gentle dewlap brushing

  • Miracle Care Antiseptic Spray – Safe antibiotic spray for minor skin infections

  • ZYMOX Ear Solution – Cleans ear wax and debris from lop ears

  • Kordon Preventive Paste for Rabbits – Nutritional supplement with vitamins

Related questions

What is a healthy weight for a rabbit?

A healthy weight for a rabbit depends on their breed, age, and frame size. As a general guide:

  • Small breeds (under 5 lbs) – ideal weight 2-3 lbs

  • Medium breeds (5-10 lbs) – ideal weight 5-8 lbs

  • Large breeds (over 10 lbs) – ideal weight 8-14 lbs

To assess if your rabbit is overweight, you should be able to feel their ribs and spine without pressing hard, and their belly should be tucked up when viewed from the side. Their dewlap may also overhang if obese.

Weigh your rabbit weekly and adjust their diet to maintain optimal weight. Provide plenty of hay, limit pellets, and feed leafy greens and veggies for a balanced, healthy diet. An overweight rabbit is prone to arthritis and other issues.

How to know if your rabbit is pregnant?

Signs that indicate your female rabbit may be pregnant include:

  • Age 4-6 months – Rabbits reach reproductive maturity at this age.

  • Nesting behaviors – Digging, shredding paper, gathering materials.

  • Enlarged nipples – More prominent around 10 days into pregnancy.

  • Decreased appetite – Often less interested in food in the last week.

  • Weight gain – Carrying growing kits adds weight.

  • Personality changes – More irritable and restless as due date approaches.

  • Discharge – Clear fluid leakage a few days before kindling.

If you suspect pregnancy, take your doe to a rabbit-savvy vet to confirm and help ensure healthy delivery. Provide extra nutrition and a quiet nesting space when the time comes. Handle kits as little as possible.

Should I get my rabbit spayed?

It is recommended to get your female rabbit spayed around 5-6 months old for these reasons:

  • Prevents uterine cancer – Unspayed does have a very high rate of cancer later in life. Neutering nearly eliminates this risk.

  • Stops reproduction – Rabbit pregnancies and caring for a litter is difficult for amateur owners. Spaying prevents accidental litters.

  • Improves behavior – Unspayed does often act territorial and aggressive. Spaying reduces hormonal behavior.

  • Increases life expectancy – Sterilized rabbits live longer healthier lives on average.

  • Reduces some health risks – Spaying may lower chances of certain conditions like uterine disease.

  • Convenience – No concerns over managing heat cycles and hormones.

Talk to your veterinarian to schedule spay surgery for your doe. While a major procedure, the long-term benefits far outweigh the risks for most pet rabbits. Be diligent with postoperative care while your bunny recovers.

Reference:
https://rabbitbreeders.us/articles/dewlaps/

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