Feeding Selection in Tortoises

Feeding Selection in Tortoises

By Assoc. Prof. Dr. Sompoch Veerakun (Ajarn Kaew), Khwankham Animal Hospital

Feeding selection in animals is a challenging management issue that can lead to nutritional deficiencies and health problems, even when caregivers try to provide appropriate diets. This often occurs because animals, especially when they are young, must learn and remember what they eat from other animals or caregivers, rather than relying solely on instinct. Therefore, feeding behavior is part of a learned process. Animals that commonly display feeding selection behavior include birds, cats, sugar gliders, and, notably, various species of tortoises.

Tortoises have an innate instinct to choose plants as their primary food source. They tend to make food choices based on factors such as light, color, smell, and taste. Some tortoises may even develop habits of chewing and swallowing foreign objects, such as ropes, shoes, nails, or shiny metals, because of the influence of light, smell, and taste. Fruits, in particular, often attract tortoises, even if they have never been fed those fruits before. The scent of fresh fruits and vegetables tends to attract tortoises more than dry food or faint-smelling items. Taste also plays a significant role in whether they continue eating or stop. For example, tortoises tend to reject leaves that have a bitter taste and high tannin content, while plants with latex, which caregivers may assume tortoises won’t eat, are often preferred.

Moreover, fresh food tends to attract tortoises more than dry food, which aligns with their natural behavior of consuming water before food in dry conditions. In these situations, tortoises may become reluctant to eat dry food and may instead prefer foods with higher moisture content. Tortoises trained to eat dry foods, such as dried leaves, grass, and pellets, are typically accustomed to an environment where water is always available, and they are often provided with a soaking bath. These tortoises do not necessarily require fresh food; however, their chances of receiving a more balanced diet are significantly increased.

Tortoises also exhibit learned behaviors through imitation. When one tortoise eats a certain food, others begin to observe and learn to eat it as well. Different plants receive varying levels of attention. For instance, the leaves of the ficus tree are more likely to be eaten than mulberry leaves, though this behavior can vary among individual tortoises. Cactus is not always a popular choice, as tortoises might eat it due to either its appeal or learned behavior.

There are many factors influencing feeding selection, and when it is observed that tortoises prefer dry food that can be easily obtained and replaced in times of food scarcity, caregivers may choose to supplement their diet with pellets to minimize the risk of nutritional deficiencies and improve growth rates. Caregivers often try different strategies to get their tortoises to eat, such as mixing fresh fruits and vegetables with other foods or altering the scent and color by coating the food with fruit like jackfruit or rose apple. Sometimes, food is mashed and formed into small pellets or piles, gradually increasing the amount over time. The best approach is to start training them to eat when they are young. Some fortunate caregivers may have tortoises that eat without much effort.

Pellets commonly used for tortoises include acacia leaves from Africa and alfalfa, which provide protein. Among the grasses, there are varieties like timothy and oat hay. These pellets often contain added minerals and vitamins. They can be used in powder form, mixed with water, and formed into small balls, which is ideal for young tortoises or those being trained. Pellets can also be sprinkled on top of fresh plants for tortoises that refuse to eat them, gradually encouraging them to learn to accept the food. Some tortoises take over three months to adapt. Caregivers need a lot of patience in such cases. However, for better growth rates, it is beneficial to supplement their diet with pellets containing probiotics, vitamins, and minerals. It is best to introduce these supplements when they are still young to encourage acceptance.

Today, tortoise pellets have advanced significantly and are fortified with minerals and vitamins to reduce common nutritional issues, such as metabolic bone disease from calcium-phosphorus imbalance and goiter from iodine imbalance. Beta-carotene, which can be found in green, yellow, orange, and red plants, as well as pellets, can replace vitamin A. Tortoises also require vitamin D3 (rather than D2), as they primarily use D3 and cannot use D2 effectively. D3 is scarce in plants, so it should be supplemented for captive tortoises that cannot select their own food properly.