For National Wildlife Week, Wild At Heart has been highlighting different animals in our care each day of the week on Facebook. For the last 3 days of the week, we are going to launch a turtle awareness campaign. Typically Wild At Heart gets 3 types of turtles in: painted turtles, Blanding’s turtles, and snapping turtles. We would like to raise awareness about these types of turtles, specifically: their natural history and identifiable traits, why Wild At Heart is seeing an increase in turtles brought in that have been hit by cars, and what you can do on an individual and community level to help turtles. On Thursday, Friday and Saturday (April 14th, 15th, 16th), more information will be added to this article highlighting a different topic surrounding turtles and their fight for survival in a growing urbanized environment.
Information written by senior animal care intern Nele van Daele and Wild At Heart staff member Monica Seidel. Photographs by interns Nele van Daele and Sarah Townson.
Figure 1: Total Number of Turtle Road Victims Brought to Wild At Heart from 2008 to 2015 (data taken from Wild At Heart animal care records).
Turtles are long-living species with a late sexual maturity which makes it very difficult to recover from increased adult death. In addition to this, they do not have the coping mechanism to produce more eggs as a response to higher mortality rates. So every adult turtle that dies on the road significantly contributes to the decline of the species in the area (Beaudry, deMaynadier, & Hunter Jr., 2008; DeCatanzaro & Chow-Fraser, 2010; Millar & Blouin-Demers, 2012).
Increased road construction and the turtle’s need to cross roads on their search for a nest often ends in severe injuries. By rehabilitating these road victims, Wild At Heart contributes to the recovery and conservation of these species. By raising awareness to this problem we hope that everyone will contribute to the conservation of these species.
The difference between Blanding’s, snapping and painted turtles
Blanding’s turtles (Emydoidea blandingii) are listed as endangered in Nova Scotia and threatened in Ontario and Quebec. Endangered species are wildlife species who are facing imminent extirpation (extinct only in a certain area) or extinction (gone from the entire planet) (COSEWIC, COSEWIC Assessment Process, Categories and Guidelines, 2015). Wildlife species that are likely to become endangered, if nothing is done to reverse the factors leading to its extirpation or extinction, are considered threatened (COSEWIC, COSEWIC Assessment Process, Categories and Guidelines, 2015).
Blanding’s turtles can be easily recognized by their yellow throat and chin (Figure 2). Their domed shell or carapace is black to brown with yellow spots and lines, and the bottom shell or plastron (Figure 2) is yellow with black spots. They are about 15 to 27cm in length, weigh between 1 and 1.5 kilogram and they become 75 years or even more (COSEWIC, 2005; MNR, 2011; CWF, 2014; MNR, 2014; Government Of Ontario, 2016).
|Figure 2: Photos of a Blanding’s turtle recovering at Wild at Heart (2016). Facial features (left), plastron (top right), and carapace (bottom right).|
Blanding’s turtles mature between the ages of 15-25. Females lay eggs every 2 to 3 years and the clutch can consist of 3 to 19 eggs. They hibernate from October to April at the bottom of wetlands (MNR, 2011; CWF, Blanding’s turtle: species information, 2014; MNR, 2014).
Snapping turtles (Chelydra serpentina) are the largest freshwater turtles in Canada. Their carapace is black, olive, or brown colored. They spend most of their time underwater, laying on the bottom of a water body or buried in the mud. Therefore they are typically covered in algae (Figure 3). The tails of snapping turtles are quite long and have triangular crests. Their size can variate between 30 to 50 centimeters, with the females are slightly smaller than the males.
The plastron is grey or yellow and is quite small compared to other turtles. Because of their small plastron they cannot completely pull in their limbs, neck, or tail. Therefore they are more likely to bite when they feel threatened. Their neck is quite long and they have strong jaws (Figure 4), so always be very cautious when handling snapping turtles (Ernst & Lovich, 2009; MNR, 2014; CWF, 2016; Government Of Ontario, 2016). Information on how to handle turtles will follow later on in this document.
Snapping turtles are currently listed as a species of special concern. Species of special concern are wildlife species that may become threatened or endangered because of a combination of biological characteristics and identified threats (COSEWIC, COSEWIC Assessment Process, Categories and Guidelines, 2015; Government Of Ontario, 2016). Snapping turtles reach sexual maturity between the ages of 15-20 (MNR, 2014; CWF, 2016).
Painted turtles (Chrysemys picta) are the turtles that can often be seen basking on logs. Their carapace (Figure 5) is olive to black colored with red to dark orange markings on the sides. The plastron is yellow with large dark irregular shapes along the midline. They have red stripes on their legs and yellow stripes on their head and neck (Figure 6). The size of painted turtles varies between 9 and 18 centimeters.
They reach sexual maturity around 5 years of age. The clutch contains from 3 to 14 eggs. Females nest from late May to early July (Ontario Nature, 2016; KTTC, 2016; Toronto Zoo, 2016).
|Figure 5: Cracked carapace of a painted turtle recovering at WAH (2016).||Figure 6: Painted turtle recovering at WAH (2016).|
All of these turtles are primarily threatened by road mortality and habitat loss. They nest in gravelly areas making roadsides an ideal location to nest, but also putting them at risk of injury from car collisions. In order to find suitable nesting site, female turtles also need to cross roads, further putting them at risk. Female Blanding’s turtles often travel up to 2.5 kilometers to find a nesting site, while snapping turtles can travel up to 10 kilometers (Beaudry, deMaynadier, & Hunter Jr., 2008; DeCatanzaro & Chow-Fraser, 2010; Millar & Blouin-Demers, 2012).
How do turtles hibernate?
Hibernation is a mechanism to cope through adverse winters in cold climates. Turtles go into an induced sleep during the winter months, and re-emerge in the spring when ideal growth and feeding conditions return. In November and December, turtles become “…very resistant to the penetration of ice into body compartments from surrounding soil, and the turtles also purge their bodies of catalysts for the formation of ice” (Packard & Packard, 2003). These changes allow them to survive in colder temperatures because water cannot organize into the crystalline phase to freeze.
All turtles must have sufficient stores to survive a long hibernation period, but also have energy when they awake from hibernation to find food and fend off predators. This fitness usually is linked to body mass in the spring (Muir, et al., 2013). The typical cold temperature at the bottom of water bodies (as seen in Northern Ontario for example) allow for the turtles to use up the stores slowly.
Therefore, turtles have to thrive through many adverse conditions to make it through the winter. This includes: cold temperatures, anoxic soil conditions, moisture content in the soil, possible freezing of the skin and skeletal musculature (but not body core), excess lactic acid build-up, and awakening from the hibernation and readily finding food while also avoiding predation. This abundance of factors is another reason that rehabilitation is so critical at Wild At Heart, because the success rate of each clutch of eggs each year is so low through hibernation.
Painted and Blanding’s turtles use finite energy reserves, not an antifreeze, to survive hibernation through their first winter. They hatch in the late summer months, but do not emerge from the nest until after their first winter is over (Packard & Packard, 2003; Storey, 2006) (see Figure 8). They survive because of the remains of a large internalized yolk sac (Storey, 2006). This strategy is beneficial because the new hatchlings avoid predation and harsh temperature conditions, and also can rapidly grow when ideal conditions return in the spring/summer. Egg size variation is dependent on both fall and spring temperatures because the turtles do not emerge from the nest until the spring (Rollison, et al., 2012).
One study found that hatchling painted turtles used an average of 0.39 kJ/g when put in a simulated 4°C wintering environment (Muir, et. al, 2013). A decrease in carapace length (0.2mm) and liver size (up to 66%) was observed in turtles hibernating in warm-winter conditions (15°C), as well as a loss in body mass of 16% (compared to 5.3% for the 4°C group) (Muir, et al., 2013). Painted turtles have skin that seems to resist the transmission of ice into their bodies, meaning they can survive sub-zero temperatures much better than Blanding’s or snapping turtles (Packard, G. C., et al., 1993). Another study found that Blanding’s turtle hatchlings survived 3 days at -3.5°C, giving them a “good” freezing tolerance (Storey, 2006). The same study found snapping turtles had a “poor” freezing tolerance, with just a 60% survival at -2.5°C after 3 days.
Snapping turtles usually emerge from nests in late summer to early autumn (Figure 8). They then move on the land to a suitable permanent water body to hibernate. The majority of turtles that do not leave the nest before winter comes die because they come into contact with the ice in the soil and there is irreversible damage to the cells. Some snapping turtles can survive a moderate stress associated with some of their bodily fluids freezing, however, all of the bodily fluids cannot freeze, and the fluids that do freeze cannot freeze for too long (Packard, et al., 1993). Fall temperatures play a factor on egg size variation for snapping turtles because that is when follicular development occurs (Rollison, et al., 2012).
Figure 8: Estimated timing of the follicular cycle of the snapping turtle (Chelydra serpentina), wood turtle (Glyptemys insculpta), and painted turtle (Chrysemys picta). Dashed arrows and light-framed boxes refer to the direct effect of temperature on follicular development (Source: Rollison, et al., 2012).
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