Do Jack Russell Terriers Have an Undercoat?

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Different dog breeds have different coats, with some being single-coated and others double-coated. Usually, double-coated dogs have different shedding levels and grooming requirements. Before adopting a Jack Russell Terrier, you may want to know whether it’s a double-coated dog or not.

So, do Jack Russell Terriers have an undercoat?

Do Jack Russell Terriers Have an Undercoat?

Jack Russell Terriers have an undercoat and an outer coat that hides and guards the undercoat. The undercoat is characterized by soft and fluffy hair that seems lighter in color.

Both the undercoat and outer coat helps protect the dog’s skin from cold weather, superficial injuries, and bug bites.

Graphic image of a white and brown Jack Russell that explains whether Jack Russell Terriers have an undercoat

In most cases, the undercoat helps regulate the dog’s temperature during season changes and temperature fluctuations. For instance, the dog sheds the lighter undercoat during autumn to give room for a thicker undercoat which will help keep it warm during the winter cold.

When the dog warms the layer of air next to its skin, the thick undercoat helps trap this air, ensuring the dog retains the warmth. On the other hand, a thinner undercoat helps the dog lose heat in summer. However, undercoats increase the level of shedding and affect the grooming requirements as follows:

  • The undercoat hairs tend to get caught by the outer coat, leading to tangles and mats. That means you’ll need to brush the dog daily or at least three times a week to prevent painful mats.
  • Considering that double-coated dogs shed more, you might need to equip yourself with an air purifier and a vacuum cleaner to help get rid of the hairs in the house, especially if you suffer from dog allergies.
  • Unlike single-coated dogs, you might need to use an undercoat grooming rake to be able to remove the loose hair from your Jack Russell’s undercoat.
  • In case the tangles and mats form, you might need to use a spray bottle to help relieve the discomfort when brushing. You might also need to work through the tangles and mats using a wide-tooth comb. However, you need to be careful when pinching the fur close to the skin to avoid accidentally injuring the skin. If the dog is uncomfortable when brushing, it means you are not gentle enough, and the dog is hurting.
  • Even after working on the undercoat, you might need to work on the outer coat with a bristle brush to improve the shine.
A close up image of a Jack Russel terrier

Jack Russell Terrier Undercoat Conditions to Watch Out For

The Jack Russell Terrier undercoat is prone to issues depending on the overall lifestyle, environment, age, and level of grooming. Some of the conditions you might need to watch out for in Jack Russell Terrier undercoats include:

Dry and Itchy Skin

A Jack Russell Terrier undercoat can trap allergy-causing substances such as dust, pollen, or grass. These substances might cause allergic reactions, making your dog’s skin dry and itchy.

Remember that external parasites such as fleas can also make your Jack Russell Terrier itchy. Some common signs of fleas are hair loss at the dog’s back and excessive itching at the base of the tail.

Although the dog might be allergic to certain foods, food allergies are short-lived, and prolonged itching should alert you to check the condition of the dog’s undercoat. You can also contact a veterinarian to help you determine the best way to groom the undercoat or control the fleas.

A side profile of a Jack Russell


Dandruff might be challenging to detect since the dog might not be itchy. That means you will need to physically inspect the condition of your dog’s undercoat and see whether the hair is dry, dull, or broken. Typically, the undercoat should be healthy and shiny without excessive white flakes.

In most cases, dandruff results from nutritional and obesity issues, and you will only need to feed your dog with well-balanced nutritious foods. However, dandruff can also signify an underlying health condition such as skin infections and thyroid issues.

Thinned Hair

It is uncommon for a Jack Russell Terrier undercoat to have bald spots even during the shedding season. In most cases, undercoat thinning results from stress, illness, or underactive thyroid gland.

These conditions might also show up in the form of excessive shedding, brittleness, or dullness of the undercoat. It’s advisable to contact a vet to help you determine the underlying health condition.

An image of a Jack

Related Questions

How Do I Wash My Jack Russell Terrier’s Undercoat?

Ensure the water goes through the Jack Russells’ undercoat onto the skin. Place a washcloth on its face and then shampoo it. Rinse the dog with adequate water to ensure the undercoat is well rinsed, and then apply a dog conditioner.

Can a Jack Russell Terrier Have an Impacted Undercoat?

Jack Russell Terriers can have impacted undercoats if they are unable to shed during the shedding season. The undercoat tangles with the outer coat, leading to matting. Depending on the extent, you might have to shave these mats.

Final Thoughts

Jack Russell Terriers have an undercoat that helps them regulate heat during the cold and hot seasons. The undercoats require regular grooming, such as daily brushing to prevent tangling and matting. You also need to ensure the undercoat is free from dandruff and allergy-causing substances.