Ukraine Part 3: Rodents underfoot

 

Signs of the Sandy Mole Rat

In the dry habitat of steppe the main sources of plant food are the leaves, flowers and seeds of the steppe vegetation and their underground storage organs in the form of roots and rhizomes. The ground is usually very hard however, which makes the kind of tunnelling moles are famous for difficult. Rodents on the other hand come equipped with perfect tools for not so much tunnelling as gnawing through the ground, and several groups of rodents have adapted to the lifestyle. In Europe and Asia these are the blind mole rats in the family Spalacidae.

These weird rodents get their name from the complete absence of eyes, which are covered by skin. Ukraine is home to five species. They have a similar lifestyle, digging extensive burrow systems containing nesting chambers, latrines and storage chambers, often many tens of metres across and many metres deep, which is where they survive the cold winters deep underground and protected from frost. Fairly large for rodents, they are mostly around the size of a brown rat or larger. They tend to be solitary animals, only meeting for the breeding season, and as they spend almost their entire lives underground their main natural enemies are snakes and animals such as foxes or other animals that can dig. Not quite as long lived as the famous (and unrelated) Naked mole rat of Africa, some individuals are still on record as reaching 15 years in captivity.

Sandy Mole Rat Spalax arenarius

One of the rarest of Ukraine’s mole rats, and endemic to the country, the Sandy Mole Rat Spalax arenarius is found east of Odessa around the lower Dnepr in sandy soils, mostly within the Black Sea Biosphere Reserve. Outside the 55km2 of total area where it can be found the few remaining populations are highly fragmented and threatened by conversion of habitat to forestry. A solitary species, as far as is known, it breeds only once each year. Currently classed as Endangered by the IUCN, the assessment is 14 years old and needs updating.

S.arenarius range

Balkan Mole Rat Spalax gracus

Not quite as threatened, but still classed as Vulnerable, the Balkan Blind Mole Rat Spalax graecus is slightly misnamed, as it does not come from Greece but rather has a range just east of the Carpathian mountains overlapping Ukraine, Romania and Moldova. Not quite as specialised as S.arenarius, it inhabits steppes, pastures and orchards, often with northern exposures. It occurs at low densities of usually only a few individuals per hectare.

S.graecus range

Podolsk Mole Rat Spalax zemni

S.zemni mounds in habitat

One of the more widespread of Ukraine’s mole rats, the Podolsk mole rat S.zemni has a range that extends over much of central and northwest Ukraine. It is mainly found on virgin steppes, but does not mind some woodland and indeed feeds on the roots of tree seedlings, although it also feeds on roots of many other plants including agricultural crops. Very little is known of its behaviour, as with other mole rats, and although it has a large range it is classed as Vulnerable and is probably declining as a result of agricultural intensification.

Podolsk Mole Rat range

Greater Mole Rat Spalax micropthalmus

One of the largest of all mole rats, the Greater Mole Rat S.micropthalmus can reach 30cm long and 570g in weight. It favours softer soils with black earth, avoiding sandy or loamy soils, and can be a pest. As a single individual can cache 15kg of food in its store chambers the impact of a large population can be large. Its main range is in the east of Ukraine extending into Russia.

Greater Mole Rat range

Lesser Mole Rat Nannospalax leucodon

Classed in a separate genus, the Lesser Mole Rat Nannospalax leucodon may actually be a complex of cryptic species. It has a large range mostly to the south of Ukraine through Greece and the Balkans, where it prefers loose soils to dig extensive burrows. As with the other species ploughing is destructive to its burrows, but it can use orchards and pastureland as well as steppe grassland. Given its range it is probably not a threatened species as a whole, but as with its relatives is probably at least locally threatened by conversion of habitat for agriculture and construction.

Lesser Mole Rat range

Northern Mole Vole Ellobius talpinus. Note the beady eyes

Not at all closely related to the blind mole rats, but with a similar lifestyle, the Northern Mole Vole Ellobius talpinus is much smaller, around 13cm long and a weight of 70g. Unlike the blind mole rats it has well developed eyes. It is also more sociable, with colonies usually consisting of a queen, several males plus one or two litters of young, with a maximum group size of up to 20 individuals, though half that is more usual. Within Ukraine it is found in the southeast of the country.

Northern Mole Vole range

So much for subterranean rodents. Among the grasses above ground there is also a large variety of rodents of various sizes, and those are what I will cover next.