Middle East blind mole rats are completely blind, their eyes being beneath a layer of skin. They rely heavily on vocalizations, olfaction, and touch. Six distinct vocalizations are used: attack, crying, invitation, courting, release, and threat calls. Courtship calls consist of a low murmur that reduces aggression between potential mates. All Spalax ehrenbergi calls are at a low frequency and are specialized for low frequency hearing. Head thumping against tunnel ceilings is also used in vibrational communication, which has shown to be advantageous in long distance communication and is used to signal territoriality and initiate mating rituals. Although the eyes of Spalax ehrenbergi are not used for visual purposes, they are still photoreceptive. In a study done by Sanyal et al. (1990), it was shown that the eyes are used for detecting photoperiodicity, which allows them to distinguish the various stages of the day.
Communication Channels: tactile ; acoustic ; chemical
Other Communication Modes: pheromones ; vibrations
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
According to the IUCN Red List, Spalax ehrenbergi is considered “data deficient,” which means there is not enough known about their population numbers to make an accurate assessment. Populations are thought to be decreasing, perhaps as a result of intensified agriculture in some areas. Middle East blind mole rats are considered common in appropriate habitat and are considered agricultural pests in some areas, where they may be persecuted.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: data deficient
Middle East blind mole rats eat roots and tubers and are considered an agricultural pest in some areas because they eat crop and disturb them with their digging. Libyans believe that touching Spalax ehrenbergi results in blindness, although to this date they have not been shown to be a vector for any human diseases.
Negative Impacts: crop pest
Although Middle East blind mole rats are often regarded as agricultural pests, they are useful in research. They have been instrumental in locating significant and important archeological sites by bringing buried artifacts and bones to the surface. They have also acted as an important species in the medical research field. Their hypoxic fossorial environment has resulted in some unique adaptations that are of interest to medical communities concerned with treating ischemia and cancer. Lastly, populations seem to be undergoing rapid speciation and there is great chromosomal and allozyme diversity within the species. It is currently being utilized as an important model species to study and elucidate the patterns and mechanisms behind speciation.
Positive Impacts: source of medicine or drug ; research and education
Spalax ehrenbergi is a primary consumer and through its diet of underground plant roots, tubers, and seeds; it shapes and defines that plant biodiversity and availability in an ecosystem. The extensive burrowing and tunneling activitie of this species also affects the water, nutrient, and air composition of soils.
Ecosystem Impact: soil aeration
Middle East blind mole rats are strict herbivores and primarily feed on the underground roots, stems, tubers, and seeds of plants. They dig extensive underground tunnels in search of food and use underground chambers to store excess, harvested food.
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Granivore , Lignivore)
Spalax ehrenbergi is widely distributed in the eastern Mediterranean region, from northeastern Libya through Egypt, Jordan, Syria, and southern Turkey. Within this region, these mole rats are found in fragmented areas with appropriate soils for burrowing.
Biogeographic Regions: palearctic (Native )
Though Middle East blind mole rats are not found in desert areas, they seem to prefer habitats with sandy and loamy soils. They are strictly fossorial and inhabit dry steppes, semi-desert, and agricultural areas, especially cultivated fields. They spend the vast majority of their lives in their underground burrows and tunnel systems. These are complex, with nesting chambers, storage areas, tunnels used for foraging, and aboveground mounds with sleeping chambers. Burrows are dug deeper in the hot months of the year.
Range elevation: 0 to 2000 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; chaparral
Other Habitat Features: agricultural ; riparian
Middle East blind mole rats lives around 3 years in the wild, but can live up to 15 years in captivity. Maximum lifespan in the wild is given as 4.5 years.
Range lifespan
Status: wild: 4.5 (high) years.
Average lifespan
Status: wild: 3 years.
Range lifespan
Status: captivity: 15 (high) years.
Middle East blind mole rat body length ranges from 150 to 270 mm and the pelage is bluish, dark gray. They are characterized by their lack of an external tail, pinnae reduced to small ridges, and subcutaneous eyes. Other fossorial morphological adaptations include robustly built and streamlined bodies with large heads, powerful limbs, and small claws. Males are larger than females.
The dental formula for Spalax ehrenbergi is 1/1, 0/0, 0/0, 3/3 = 16. The two large incisors are orthodont and are oriented in front of the lips so that the incisors can be used to dig even when the mouth is closed. The cheek teeth are rooted and display enamel patterns that resemble the letters "z" and "s."
Spalax ehrenbergi has a highly polymorphic karyotype with over 30 chromosomal forms. It has been posited that some of these forms are likely to be distinct species. It has been suggested that at least four distinct cryptic species (Spalax carmeli, Spalax galili, Spalax golani, and Spalax judae) exist.
Range mass: 250 to 400 g.
Range length: 150 to 270 mm.
Range basal metabolic rate: 0.62 to 1.03 cm3.O2/g/hr.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Sexual Dimorphism: male larger
Spalax ehrenbergi has adapted to a strict fossorial lifestyle, which provides good protection from most predators. No natural predators are reported in the literature, although they are sometimes persecuted by humans.
Anti-predator Adaptations: cryptic
Females only mate with one male for each breeding season, but may mate with different males throughout their lifetime, making them serially monogamous. Spalax ehrenbergi mating behavior is categorized into three stages: agonistic, courtship, and copulation. Courtship takes place during the winter season, which is the only time males and females will be found in overlapping territory. This species is highly aggressive, with severe aggressive displays occurring within and between the sexes. Due to their aggressive nature, courtship is a very long process involving the male and female engaging in repeated mating displays until their aggressive behavior is attenuated. Seismic signaling is used to initiate the first contact between the male and female's respective burrows. This involves both males and females drumming their heads against the ceilings of their burrows to create vibrations. The mating pair begins with face-to-face touching of their incisors which proceeds to nibbling and courtship calls, which contributes to reducing the intensity of the aggressive displays between the pair. After the courtship ritual the male will dig a “copulation hollow” which is where the actual mating will take place. After the pair becomes habituated to the hollow the female will initiate copulation by turning her back towards the male. Immediately after copulation the male will fill in the “copulation hollow” and the pair will separate and return to solitary lifestyles.
Mating System: monogamous
Middle East blind mole rats breed in the winter, from November to March. Females construct elaborate breeding mounds and nesting chambers in preparation for breeding. Gestation lasts 34 days and the average litter size is 3 to 4 (range 1 to 5) pups. Young are born from January to April. As the offspring develop, aggressive interactions between the pups increase to the point where they are forced to disperse from each other. Once the pups begin dispersing, the mother reciprocates aggressive displays to aid in kin dispersal and ensure her young do not attempt to settle in her territory. Young are independent at 4 to 6 weeks old. Time to first reproduction is not reported, but is likely to be within their first year of life.
Breeding interval: Females seem to breed once yearly.
Breeding season: Middle East blind mole rats breed in the winter, from November to March.
Range number of offspring: 1 (low) .
Average number of offspring: 3 to 4.
Average gestation period: 34 days.
Range time to independence: 4 to 6 weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Females provide sole parental care. In a study done by Gazit and Terkel (2000), males exhibited limited parental care and intermittently brought food to the female’s territory if the males had acquired a large food surplus during the wet season. The young are born naked and helpless but develop quickly, leaving the nest and becoming independent at 4 to 6 weeks old.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
The Middle East blind mole-rat or Palestine mole-rat (Nannospalax ehrenbergi) is a species of rodent in the family Spalacidae.[2]
It was formerly classified in the genus Spalax, but more recent phylogenetic evidence supports it and two other species belonging to the genus Nannospalax. Of the three Nannospalax species, N. ehrenbergi is the only one to also belong to the subgenus Nannospalax (unless the potential species within N. ehrenbergi are also considered their own species).[3]
Cytogenetic studies have shown N. ehrenbergi in Israel may actually be a species complex containing several cryptic species with chromosome numbers 2n=52, 2n=54, 2n=58 and 2n=60. Close to the 'border line' of the niche of each subspecies there is mating between individuals from different subspecies/different 2n chromosome number. Birth of fertile offspring implies that speciation of the subspecies has not been completed.[4]
In 2001, four new Nannospalax species (then classified within Spalax) endemic to geographical regions within Israel, Palestine and the Golan Heights were described based on chromosome divergence by a team of researchers led by Eviatar Nevo. These were:[5]
Although the ITIS and Mammal Species of the World still recognize these species, the American Society of Mammalogists and the IUCN Red List presently group these within N. ehrenbergi due to taxonomic uncertainty, such as lack of convincing genetic support for speciation, and the type locality of ehrenbergi itself likely falling within the range of one of these species.[6][7][8]
The Middle East blind mole-rat weighs 100–200 grams (3.5–7.1 oz). It has light gray fur and four sharp teeth, two large teeth in the upper jaw and two smaller teeth in the lower jaw. It has a life span of up to 20 years and is notable for its adaptability to severe lack of oxygen. In Israel, the blind mole-rat is a major agricultural pest. It digs long tunnels up to 80 centimeters deep and stores onions and tubers in underground chambers.[9] The exceptional ecological adaptation strategies of the blind mole-rats can be seen in their different tongue morphologies, as evidenced by their tongue papillae. The tongue papillae differ between individuals in a species to adapt to different environmental regions with variant soil characteristics and food types.[10]
N. ehrenbergi is found in Egypt, Iraq, Turkey and the Levant (Israel, Syria, Palestine, Jordan and Lebanon). The natural habitat of the mole is Mediterranean-type shrubbish vegetation, and it is threatened by habitat loss.
According to Israeli researchers at Haifa University, the Middle East blind mole-rat is an important lab animal for researching cancer due to its apparent resistance to the disease.[9] In a 2013 study, data on N. ehrenbergi resistance to cancer was documented:[11]
-No spontaneous tumors have ever been noticed in blind mole rat, based on observing thousands of individuals along half a century.[11]
-Inducing cancer with chemical carcinogens that lead to 100% of the expected tumors in mice and rats after 2–6 months, respectively, indicate an extraordinary cancer resistance of Spalax: Only 2 out of 12 animals, and old ones (>10 years old; Spalax can live ~>20 years; 5 times longer than its evolutionary relative, the rat) developed the expected tumor with one of the carcinogens and only after 18 and 30 months.[11]
- Nannospalax cells (fibroblasts), and only Nannospalax cells, when grown in co-culture with cancer cells from different species, including a wide range of human cancer cells, kill the cancer cells. This is also true when "feeding" the cancer cells with the medium that Nannospalax cells grew in. Identification of the secreted substance/s by Nannospalax fibroblasts and the component on cancer cells' membrane they interact with, that lead to the cancer cells' death, can open a possibility for finding a general cure to cancer.[11]
Cancer resistance has also been noted in the two former species (N. judaei and N. golani) presently merged with this species.[12] N. galili had its genome sequenced in 2014.[13]
Studies on the growth of fibroblasts in vitro of N. judaei and N. golani showed that the process of necrosis replaces the role of the systematic apoptosis normally used in most organisms. Generally low-oxygen conditions, such as those common in blind mole rats’ burrows, usually cause cells to undergo apoptosis. One study showed that in adaptation to a higher tendency of cell death, blind mole rats evolved a mutation in the tumor suppressor protein p53, also used in humans, to prevent cells from undergoing apoptosis.[14] Human cancer patients have similar mutations, and blind mole rats were thought to be more susceptible to cancer because their cells cannot undergo apoptosis. However, after a specific amount of time (within 3 days according to one study), the cells in blind mole rats release interferon-beta (which the immune system normally uses to counter viruses) in response to over-proliferation of cells caused by the suppression of apoptosis. In this case, the interferon-beta triggers cells to undergo necrosis, and this mechanism also kills cancer cells in blind mole rats. Because of tumor suppression mechanisms such as this, blind mole rats and other spalacids are resistant to cancer.[15][16][17]
The involvement of interferon in the so-called concerted cell death of Spalax cells via necrosis was highly disputed.[15] Serious questions have been raised on the inconsistent methodology used that led to this speculation.
Observing the dirt displaced by burrowing mole rats can help archaeologists decide where to dig, since it often contains small artifacts like potsherds.[18][19]
The Middle East blind mole-rat or Palestine mole-rat (Nannospalax ehrenbergi) is a species of rodent in the family Spalacidae.
