Icelandic Horses

Thermoregulation in Icelandic Horses

Icelandic horses are a unique breed that has adapted to the harsh climate of Iceland, where temperatures can range from -30°C (-22°F) in the winter to 20°C (68°F) in the summer. As a result, these horses have developed a range of thermoregulation strategies that allow them to maintain their body temperature within a narrow range of values. Here are some of the key thermoregulation strategies used by Icelandic horses:

  1. Shaggy Coat

One of the most distinctive features of Icelandic horses is their thick, shaggy coat. This coat is made up of two layers: a long, coarse outer layer that provides protection from the elements, and a soft, dense undercoat that helps to trap heat close to the horse’s body. The shaggy coat is particularly effective at insulating the horse in cold weather, and can also help to repel rain and snow.

  1. Huddling

Like many other animals, Icelandic horses will huddle together in cold weather to conserve heat. This behavior allows them to share body heat and stay warm in harsh conditions. Huddling is particularly important for young foals, which are more vulnerable to cold temperatures and rely on the warmth of their mothers and herd mates to stay warm.

  1. Reduced Activity

During cold weather, Icelandic horses will often reduce their activity levels in order to conserve energy and heat. This can include standing still for extended periods of time, or even lying down in the snow to minimize heat loss. While this may seem counterintuitive, it is an effective way for the horses to conserve their energy and maintain their body temperature in harsh conditions.

  1. Brown Fat

Like many other mammals, Icelandic horses have brown adipose tissue (BAT), which is a specialized type of fat that is involved in thermogenesis. Brown fat contains a high number of mitochondria, which are responsible for generating heat through metabolic processes. Icelandic horses can activate their brown fat in response to cold temperatures, which helps to generate heat and maintain their body temperature.

  1. Water Intake

In addition to these behavioral and physiological strategies, Icelandic horses also regulate their body temperature through their water intake. During cold weather, horses may reduce their water intake in order to avoid the need to urinate, which can cause them to lose body heat. However, it is important for horses to maintain adequate hydration, as dehydration can also impair thermoregulation and overall health.


Icelandic horses have evolved a range of thermoregulation strategies that allow them to thrive in the harsh climate of Iceland. These include their shaggy coat, huddling behavior, reduced activity, brown fat activation, and water intake regulation. By utilizing these strategies, Icelandic horses are able to maintain their body temperature and overall health in a variety of environmental conditions.