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Why Does My Gerbil Look Greasy? (Explained)

Seeing your gerbil having greasy fur can cause concern for a gerbil owner. Why is this so? Are they sick? What can be done about it? These are the many questions that pop up.

Well, there are reasons why this is so. In this article, we will go into detail about why a gerbil can look greasy and what to do about it.

Why Does My Gerbil Look Greasy?

A gerbil may look greasy because of the oily secretions they produce from their harderian glands which they spread on their fur through grooming. This gives a gerbil a greasy or oily look which is natural with no need for concern.

Greasy gerbil fur is natural and is related to the temperature of its surrounding environment. When the environmental temperature is low and cold you will notice the greasy look more.

gerbil with greasy look

Let’s go into a deep dive into why the oil secretions from the harderian glands are produced, the oil’s function, the influence of the environment, and what you can do.

The harderian gland in gerbils

The harderian gland is a pigmented gland found directly behind the eyes and around the eyes of most vertebrate animals. This includes most mammals, reptiles, and birds. 

In gerbils, the harderian gland is found behind the eye and produces a liquid that drains out through the tear duct.

The secreted fluid from the gland is rich in pigmented lipids (fats) which have several functions. These functions include:

  • Lubrication of the eyelids and eyes
  • Acts as a source of saliva 
  • The photoprotective function of the eye
  • A pheromone source for attracting other gerbils
  • Immune defense for eyes against infection
  • Source of growth factors
  • Osmoregulation function, that is, maintenance of osmotic pressure of the eyes
  • Thermoregulation: A source of oils that can be used to regulate body temperature

All these functions are important in the survival of a gerbil. The thermoregulation function is what we will focus on because this is what causes the greasy look of a gerbil.

Wild gerbils can survive extreme temperatures between 120 to – 40 degrees Fahrenheit. The ideal optimal temperature for them in homes is between 65 to 75 degrees Fahrenheit.

Depending on the environmental temperatures whether hot or extremely cold, gerbils have the ability to regulate their body temperature. 

In hot weather, gerbils will use their saliva to cool down.

They do this by spreading their saliva all over their fur. The saliva then evaporates and causes a cooling effect which relieves them of the heat.

During cold temperatures, gerbils survive the low temperatures by:

  • Cuddling together to share their body heat
  • Dig Burrows to keep warm in tunnels
  • Thermoregulation through harderian gland secretions

When the temperatures are cold a gerbil produces the lipid fluid from the harderian gland.

They then spread the secretions all over their fur through grooming to ensure coating of the fur with the lipid. The fats spread on the fur gives a gerbil a greasy appearance.

The lipids (fats) provide insulation and protect them from cold and moisture. 

The pigments within the fluid, also known as porphyrins, are reddish-brown in color and darken the fur which encourages heat absorption from the limited sun rays in cold weather. 

This warms them up and they are able to survive cold temperatures.

A study conducted on the importance of this gland in thermoregulation showed that removal of this gland reduced a gerbil’s ability to withstand wetness and cold temperatures at 3 – 5 degrees celsius. 

This shows the usefulness of this gland’s secretions during cold weather for a gerbil to survive.

When temperatures get hot for them after covering themselves with the lipid secretions from the harderian glands, a gerbil will want to remove them from their fur to cool down. 

They do this by sand bathing by rolling in the sand to remove the fats and pigment which helps in air circulation within the fur.

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What to do

Production of the lipid secretions from the harderian glands is a natural body reaction to help a gerbil survive their environment. Therefore there is no harm to them. 

However, production of it for thermoregulation by covering themselves in the secretions indicates that your gerbil is feeling cold.

There are a few things you can do to make your gerbil comfortable. This includes:

Keeping them warm during winter

During winter it is important to keep your gerbil warm by providing a conducive environment. You can do this by increasing the room temperature to an optimal temperature.

Also, provide more bedding to enable them to bury themselves in it. This helps them retain body heat which keeps them warm.

The bedding should be at least 2 to 3 inches deep.

Provide exercise wheels in their cage so that they can also utilize them to run and generate natural body heat. This will also help them to be warm.

Relocate the gerbilarium 

Move your gerbil’s gerbilarium to a warmer room if their current room is a bit cold.

You can also make sure that the cage is away from windows or open doors that can bring in cold air drafts.

Also, ensure that you do not put their cage under direct sunlight or next to a heater because their body temperature will quickly rise which will make them too hot and uncomfortable.

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Provide a sand-bath

When temperatures increase, your gerbil will want to remove the lipid secretions from their fur to cool down.

Provide a sand bath constantly in a corner in their cage or at least once a week for them to roll in to enable them to do this. 

Place sand in a ceramic bowl which they cannot damage by chewing or topple over while rolling in it.

Gerbils are desert animals so they really like a sand bath.


It can be alarming to see your gerbil is all greasy and not the normal self.

The good thing is that this is a very natural occurrence with no medical concern and it is a natural body response to their environment especially if it is cold.

Provide your gerbil the resources they need to make sure they are comfortable by creating a conducive living environment.

I hope this article was able to put you at ease on why your gerbil looks greasy and what you can do about it. 


The harderian gland: a tercentennial review

Harderian Gland