Voles are small, stocky rodents found across temperate zones, primarily recognized by their short tails and preference for dense ground cover. These herbivores transition from a completely liquid diet to one composed of tough, high-fiber plant matter. The dietary needs of a baby vole change dramatically in their first few weeks of life, directly influencing their rapid growth and eventual independence.
Neonatal Diet: Relying on Milk
The initial period of a vole’s life involves complete reliance on its mother’s milk, typically lasting 10 to 14 days post-birth. This specialized milk fuels the neonate’s fast growth rate by providing concentrated nutrients. Vole milk, particularly among Microtus species, is notably high in protein (approximately 16%) and fat (7%), with a comparatively low lactose level (3% to 4%). This profile is typical for small, altricial mammals that need to double their birth weight quickly. The high energy density allows pups to develop rapidly, achieving milestones like developing fur and gaining mobility.
The Weaning Process: First Solid Foods
The transition away from milk begins around day 10 to 14, marking the start of weaning. This nutritional shift requires the young vole’s digestive system to adapt from processing highly digestible milk to breaking down complex plant cellulose. The mother initiates this change, and the pups begin exploring outside the nest.
The first solid foods are typically soft, easily digestible plant materials, which the mother may bring into the nest or which the pups encounter nearby. These initial foods often include tender, young grass shoots, soft roots, and the inner pith of plant stems. Soft vegetation helps prevent digestive upset while the gut populates with the microbes necessary to ferment fibrous material.
This shift requires a change in digestive enzyme production to handle the increasing load of carbohydrates found in plant matter. The introduction of solid food is a learning process that prepares the young vole for the adult herbivorous diet. During this time, they consume both milk and solids, gradually increasing their intake of vegetation as their digestive capabilities mature. Weaning generally concludes by 21 days of age.
The Juvenile Diet: Foraging Like Adults
Once fully weaned, the juvenile vole adopts a diet nearly identical to that of an adult, focusing on high-fiber vegetation. As herbivores, their diet is primarily composed of grasses, sedges, and herbaceous plants. They use sharp incisors to gnaw through tough stems and roots, consuming approximately 60% or more of their body weight daily to sustain their high metabolism.
The vole’s burrowing behavior is linked to its diet, as they tunnel to access underground food sources like roots, tubers, and bulbs. This subterranean feeding is important during colder months when above-ground vegetation is scarce. In autumn, they consume and cache seeds, nuts, and fruits for winter stores.
During the winter, when fresh growth is unavailable, the diet shifts to include the inner bark and small roots of woody plants, often accessed beneath the snow line. Although primarily herbivores, voles occasionally consume small insects or scavenge carrion when plant food is difficult to find. This mature diet is high in fiber and low in protein compared to neonatal milk.
Considerations for Orphaned Voles
Finding a baby vole without its mother requires caution, as human intervention often leads to poor outcomes due to the species’ specific needs. The most important step is to contact a licensed wildlife rehabilitator immediately, as they possess the knowledge and specialized feeding tools. A baby vole found alone should first be kept warm in a dark, quiet container using a heat source placed under only half of the box.
It is important that a found baby vole is not given cow’s milk, human infant formula, or any pet formulas not specifically designed for wild rodents. These inappropriate substitutes can cause severe gastrointestinal distress, aspiration pneumonia, or fatal bloating. While awaiting professional assistance, some rehabilitators may use a diluted kitten milk replacer as a temporary measure due to its higher protein and fat content compared to cow’s milk. Attempting to force-feed an injured, cold, or dehydrated baby can be fatal, as its body may not be able to digest the nutrients.