Physical Characteristics
The Blanding's turtle (Emydoidea blandingii) is one of the longest-lived (greater than 70 years) and slowest maturing turtles (20+ years).  It has a moderately high-domed carapace (top shell) spotted or streaked with greyish-yellow.  Coloration between individuals is highly variable. In Nova Scotia, adult carapace length ranges from 18 to 25 cm.  Males are typically larger than females.

Its plastron (lower shell) is formed from a series of scutes (plates), each of which is yellow with irregular black spots in the outer corner.  In juveniles, annual growth rings are easily visible on each scute.  Its shell is semi-hinged, allowing the turtle to pull its head and limbs in for defense. Colour on the top and sides of the head varies from black to brown to olive with yellowish spots or mottling. In sharp contrast with the rest of the turtle, the chin, throat, and underside of the long neck are bright yellow. It appears to have a permanent "smile" because of the notch in its upper jaw. 

Natural History
Although the ancestral habitat of Blanding's turtle was likely prairie marsh, today populations occur in both prairie and forested regions. Macro-habitats include lakes, ponds, fens, marshes, low fields, ditches, creeks, river sloughs, and bogs.  Within these macro-habitats, Blanding's turtles tend to frequent shallow water containing submergent or emergent vegetation, often with deep, organic sediments.   

Blanding's turtle is an aquatic predator that feeds at several levels of the food chain. Food items include frogs (adults, tadpoles and eggs), insect larvae and nymphs (especially dragonflies), freshwater snails, leeches, and small fish, as well as vegetable matter (including cow lily seeds).  Feeding mostly occurs underwater and food seized on land is generally carried to the water for swallowing. Prey is either swallowed whole or if it is too large it is held by the jaws and shredded into smaller pieces by the front claws (Harding 1997).

Eggs and hatchlings are preyed upon by a variety of generalist predators including raccoons, skunks, ravens, short-tailed shrews, and ants.  Few hatchlings (less than 1%) survive to adulthood.  Once they reach adulthood, they are largely free from predation, with the exception of encounters with vehicles.

Fertilization in Blanding's turtles is internal, with copulation taking place in the water. Mating occurs year-round in Nova Scotia with the peak in the fall.  Nesting occurs in June and early July.  Females may travel considerable distances from the water to find suitable nest sites to lay their eggs.  In Nova Scotia they nest in a variety of habitats including lakeshores, rocky outcrops, roadsides and gravel roadbeds and other clearings created by humans.  Although elsewhere the species nests in sand and soil, in Nova Scotia, nesting substrates are predominantly cobble and gravel.

Using alternating movements of the hind feet the female digs a nest cavity 8 to 15 cm deep and 7 to 10 cm in diameter at the mouth. She lays an average of 10 (5 to 15) flexible, elliptical eggs about 3.6 cm long. After the eggs are laid, the female carefully buries and conceals the nest; she then leaves without ever seeing the nest. The entire nesting process, which usually occurs in the evening, can take anywhere from 1 to 7 hours.

Hatchlings emerge approximately 90 days later, depending on the temperature and moisture in the nest.  The sex of Blanding's turtles is determined by the temperature at which they were incubated; eggs incubated at low temperatures (below 25C) produce nearly all males and those incubated at higher temperatures (above 30C) are nearly all females. The success of Blanding’s turtle nests is highly variable. Even if a nest does not get depredated, it often fails either completely or partially due to flooding, poor incubation conditions, infertile eggs and other factors.

Distribution of the Blanding's Turtle
Throughout its range Blanding's turtle is patchily distributed, especially in peripheral regions.  Its fragmented range extends from extreme southwestern Quebec and southern Ontario west to Minnesota and Nebraska and south to central Illinois. Nebraska and Minnesota presently support the largest populations. Isolated local populations occur at the western periphery of the main range in Minnesota, Wisconsin, and at the eastern periphery in New York, Maine, Massachusetts, New Hampshire, and Nova Scotia.  Follow this link for a more detailed map of the North American distribution.  [Click Images to Enlarge]

In Nova Scotia, the Blanding's turtle reaches the northeastern periphery of its range and exists only in several small separate populations in the southwestern interior of the province.   Confirmed sightings are limited to the Mersey and Medway watersheds, with yet unconfirmed additional sightings in the LaHave, Roseway and Bear River watersheds. We currently recognize three distinct populations in Nova Scotia, one in Kejimkujik National Park and National Historic Site and two in working landscapes on the Medway watershed.


Historical Knowledge of Distribution
Blanding's turtles were not reported in Nova Scotia until 1953. Although nothing is known of the history of the species in Nova Scotia, a comparison of past and present distributions over the entire range shows that the species' distribution has changed considerably.  Fossil evidence, which occurs to the south and west of the centre of the present distribution, suggests that the species' range has shifted eastward since the last glaciation. This shift may have resulted from habitat disappearance and changing climatic conditions. Of the known disjunct populations, the Nova Scotia population is the most isolated and is thought to have become established during a warmer climatic period.

Nova Scotia Population of Blanding's Turtles
Blanding's turtles in Nova Scotia exist as a population complex well isolated from the rest of the species range.   Over the past decade research has revealed some significant differences between Blanding’s turtles in Nova Scotia and those in the main range. In Nova Scotia: 

  • Nesting occurs later (June and July) and eggs have an extended incubation 
  • Many turtles nest on lakeshores, rather than inland
  • Nesting substrates are predominantly cobble and gravel; whereas elsewhere the species nests in sand and soil
  • Clutch success and recruitment into the breeding population are particularly hindered by regional environmental constraints (e.g., cooler incubation season, nest flooding) and high rates of nest and juvenile predation 
  • Turtles grow more slowly and mature later (20-25 years) than in many other populations
  • Although the species covers a limited geographic area and exists in low numbers, the three known populations are distinct. Populations are genetically distinguishable suggesting that there is very little movement of turtles between them. Differences in behavior, habitat use, growth rates, adult size and clutch size have also been recorded among them. 
  • The species has significantly diverged genetically from populations in the main range and harbours a significant portion of the total genetic biodiversity of the species
The unique nesting behaviour and habitat selection may represent adaptations to the thermal constraints on incubation at the northeastern limit of the range. It may also reflect limited opportunities for finding mates, due to low density, and limited availability of suitable nesting sites for females. 


Blanding's Turtle Status

Nova Scotia population: In 2005 COSEWIC (Committee on the Status of Endangered Wildlife in Canada) uplisted the Nova Scotia populations of the Blanding's turtle from  "Threatened" to "Endangered" based partly on a Population Viability Analysis that indicated the KNP population was declining. In 2000, under newly enacted endangered species legislation, Nova Scotia declared the Blanding's turtles "Endangered".  These decisions were based, in part, on the species’ limited distribution within the province, the population’s uneven age structure, and the low rate of recruitment into the breeding population. 

Status Elsewhere: In Canada, Blanding's turtle is protected (i.e., may not be collected or disturbed) in all national parks where it occurs.  In Ontario, the species has been protected since 1984 under the Game and Fish Act. In the United States, Blanding's turtle is protected in the states of New York, Michigan, and Minnesota and considered threatened or endangered in Missouri, Wisconsin, Maine, New Hampshire, Massachusetts, Iowa, and Pennsylvania. The species has been extirpated from Rhode Island and Connecticut. Internationally, the World Conservation Union (IUCN) ranked the species in 1996 as "Lower risk: near-threatened".  

More Information on How Status is Determined
For a more in-depth description of the Nova Scotia General Status Ranking system, the Nova Scotia Endangered Species Act, or the federal COSEWIC ranking system please visit the following sites.

General Status of Wild Species of Nova Scotia

A Nova Scotia Department of Natural Resources site which describes the general status ranking procedure and provides a searchable database of all wild species of the province.

Nova Scotia Endangered Species Act

The Nova Scotia Endangered Species legislation as a document on the legislature's web site.  

COSEWIC Background Information
COSEWIC, the Committee on Status of Endangered Wildlife in Canada is a body of government, academic and non-government experts that designates species at risk as extinct, extirpated, endangered, threatened or vulnerable. This Environment Canada site describes what COSEWIC is and its role in assessing the level of risk of extinction for Canada's wildlife species. 

COSEWIC Species at Risk Search
This Environment Canada site provides a searchable database on all species in Canada. You can search by province, species, and federal COSEWIC risk

IUCN Background Information
This World Conservation Network site provides information on the criteria and categories for IUCN red list rankings.