Nova Scotia Herpetofaunal Atlas

Eggs


Identifying Herp Eggs

Welcome to our new webpage on egg identification! Many of you have wondered how to identify reptile and amphibian eggs, so we decided to put together a preliminary guide. We expect this guide to evolve as we obtain new information, so please share your knowledge, especially if it relates to Nova Scotia! If you have any doubt whatsoever about your egg identification, please do not enter the information as an atlas record. If you would like more help with egg identification, feel free to send us a picture. Pictures taken with the subject next to a ruler and with information on the number of eggs, habitat type, and time of year are the most useful.

Remember that eggs are future adults: damaging or destroying eggs, however inadvertent, reduces a population's ability to survive and can lead to population declines. Please allow herp eggs to develop in peace. In particular, remember that turtles are very vulnerable to predators and avoid disturbing nesting turtles. Never dig up developing eggs. Instead, examine the shells once the eggs are hatched.

Salamanders
Yellow-spotted Salamander
Blue-spotted Salamander
Eastern Redback Salamander
Four-toed Salamander
Red-spotted Newt
Frogs
Eastern American Toad
Spring Peeper
Wood Frog
Leopard Frog
Pickerel Frog
Mink Frog
Green Frog
Bullfrog



Reptiles
Snakes

There are only two snake species that lay eggs on Nova Scotia, the Smooth Green Snake and the Ringneck Snake. The way to tell the eggs of the two apart is to look at their colour and shape. Smooth Green Snake eggs are white and cylindrical whereas Ringneck Snake eggs are yellowish and comma-shaped or straight with one fat end. Otherwise, clutch size and egg size are similar in both species. Smooth Green Snakes lay 3-8 eggs that range in size from 19-37mm and Ringneck Snakes lay 1-8 eggs that range in size from 21-36mm. Both species lay their eggs under rocks or rotting wood, seeking the sauna-like conditions created by a damp substrate and a rock/wood surface heated by the sun. Both species sometimes lay their eggs in communal nests, so if you find dozens of eggs together, you've found the reproductive output of several females. Ringneck Snake eggs hatch in 2 months and the hatchlings mature in 2-3 years. Smooth Green Snake eggs hatch in 1-3 weeks and the hatchlings can mature in their second year.

Ringneck Snake eggs

Smooth Green Snake eggs


Photo: NS Museum of Natural History. Photo from Nova Scotia.

Photo: NS Museum of Natural History. Photo from Nova Scotia.


Turtles

All turtles lay their eggs in sand, gravel or cobble areas, including exposed river bars, beaches, and road, railroad or bridge embankments. Often people find the hatched, dried and distorted eggshell fragments, and in that case it is difficult or impossible to tell whether the original shape was spherical (completetly round like a ping pong ball) or ellipsoid (elongated like a typical bird's egg but equally rounded at both ends).

Snapping Turtle
Snapping Turtles lay 20-40 eggs per clutch from late June to early July. The eggs are spherical and 28.5-35.5mm in diameter.

Photo: NS Museum of Natural History. Photo from Nova Scotia.

Wood Turtle
Wood Turtles also lay their eggs in late June to early July, but there are fewer eggs per clutch (4-12 eggs) and they are ellipsoid in shape (3-4 cm long). Wood Turtles generally move farther from the water to lay their eggs than Snapping Turtles.

Blanding's Turtle
Blanding's Turtles lay their eggs slightly earlier, starting in early June and continuing to early July. Females lay 10-12 eggs per clutch. The eggs are ellipsoid and somewhat larger in diameter than Wood Turtle eggs.

Photo: NS Museum of Natural History. Photo from Nova Scotia.

Painted Turtle
Painted Turtles lay their eggs at the same time as Blanding's turtles (early June-early July), but lay 5-10 eggs per clutch. The eggs are ellipsoid and are about 3.3 cm long and 2.3 cm wide.

 

Amphibians

Sometimes amphibians eggs are easier to find than the adults, so it can be a great way to complete target squares without spending a lot of time looking. This is especially true for species such as Wood Frogs and Yellow-spotted Salamanders, whose eggs are readily found in early spring.

Many amphibian eggs can be identified by the time of year they appear, whether they are laid in masses, the number of eggs per mass, and the shape of the egg mass. Keep these key features in mind as you embark on your egg identification odyssey.

 

Salamanders

Yellow-spotted salamanders
Time: Early spring (April mid-May)
Description: Globular or sausage-shaped egg masses. When first laid, egg masses are very compact (6-6.5 cm in diameter), but after they absorb water, they swell to over 10 cm in diameter. Each egg is surrounded by a conspicuous clear or slightly cloudy gelatinous envelope forming an egg capsule. The vitelline membrane is about the width of an ovum away from the ovum. Interestingly, a green alga often grows within each egg capsule giving the egg mass a greenish colour. By supplying oxygen, the alga promotes larger embryos, which hatch earlier and are more likely to survive. Wood Frog and Yellow-spotted Salamander egg masses can be confused. Note that Wood Frogs deposit many more eggs in each egg mass than Yellow-spotted Salamanders.
Clutch Size: Each female lays 2-4 egg masses, which each contain 100-400 eggs. If disturbed, females can lay smaller egg masses (15-20 eggs).
Egg Habitat: Females lay eggs in woodland ponds, vegetated coves of lakes, quiet vegetated portions of streams, and roadside ditches. These water bodies may be ephemeral. Egg masses have never been observed from lakes with large predaceous fish. Egg masses are attached to submerged vegetation or rest on the bottom. Several females may use the same spot to lay their eggs, so you may see several masses together (picture at bottom or right).
Time to hatch: 1-2 months depending on water temperture.

Photos: Jim Wolford (left or top) and Dave Harris (right or bottom). Photos from Nova Scotia.

Blue-spotted salamanders
Time: Early spring (April mid-May)
Description: Females lay their eggs either individually or in little groups of 2-30 eggs. The egg masses tend to be rather loose unlike the firm consistency of Yellow-spotted salamander egg masses. The jelly around the eggs is quite clear and the vitelline membrane around the ovum is very near to the ovum.
Clutch Size: Each female lays approximately 70-550 eggs per year.
Egg Habitat: Eggs are laid in shallow woodland ponds and ditches that do not contain large, predaceous fish. Eggs are placed on the bottom or at the base of vegetation or rocks.
Time to hatch: 3-4 weeks.

Blue-spotted Salamander egg masses to the left and right of the larger, central Yellow-spotted Salamander eggs
(Photo:
Massachussetts Vernal Pool Association )

Eastern Redback Salamander
Time: Summer (June and July)
Description: These salamanders are the only ones in Nova Scotia that lay terrestrial eggs. They are also one of the few herps to provide parental care to their young. Females guard their eggs for 6-8 weeks and remain with the hatchlings for 1-3 weeks. Females aggressively drive off other female Red-backed Salamanders by biting, snapping and lunging. If a brooding female is unable to drive off the intruder, the intruder may eat the eggs. When females are removed from the nest, egg survivorship is very low. Each egg is 3-4mm in diameter and is surrounded by two jelly envelopes resulting in a total diameter of 3.5-5mm.
Clutch Size: Females lay 4-17 eggs in small clusters.
Egg Habitat: The females lay their eggs in cavities inside moist rotting wood or under thick mats of moss.
Time to hatch: Eggs develop directly (no larval stage) and the juveniles, which look like miniature adults, hatch after 1-2 months in August or September.

 
Photo: Jim Wolford. Photo from Nova Scotia.

Four-toed Salamander
Time: Early spring (April to mid-May)
Description: Female Four-toed salamanders lay their eggs in small clusters in sphagnum moss slightly above water, and remain with the eggs until they hatch. If nesting habitat is scarce, several females may lay their eggs together in a communal nest with one or two females in attendance. Eggs are 2.5-3mm in diameter and are covered by two jelly envelopes.
Clutch Size: Females lay approximately 20-40 eggs per year.
Egg Habitat: Eggs are laid within sphagnum moss hummocks a few centimeters over water so that the larvae can drop into water once they hatch.
Time to hatch: Six to eight weeks.


Photo: Nova Scotia Museum of Natural History. Photo from Nova Scotia.

Red-spotted Newts
Time: Spring (April to June)
Description: These eggs are very difficult to find because the females lay them singly. Females only lay a few eggs per day, so it takes her several weeks to lay the entire clutch. Eggs are 1.5mm in diameter and are surrounded by a three jelly envelopes. Vegetation often adheres to the sticky outer envelope.
Clutch Size: Females can lay approximately 80-450 eggs per year.
Egg Habitat: Females attach their eggs to the bottom or to submerged vegetation, rocks, and sticks.
Time to hatch: An aquatic larval newt hatches from the egg in 1-2 months.

We are on the lookout for pictures of Red-spotted Newt eggs. If you have any, please let us know!

Frogs

Eastern American Toad
Time: Late spring (May)
Description: Toads are the only Nova Scotia amphibian to lay their eggs in strings. Females lay one string from each oviduct producing a double strand of eggs. Each strand is only a couple of eggs wide, but it is several meters long. Strands often become tangled and covered in silt.
Clutch Size: Females lay 4,000-8,000 eggs.
Egg Habitat: Lake and pond shallows. Toads avoid laying eggs in areas where Wood Frog tadpoles are present.
Time to hatch: 2-8 days.

 
Photo: Jim Wolford. Photo from Nova Scotia.

Spring Peepers
Time: Spring (April-May)
Description: Like the Red-spotted Newts, female Spring Peepers lay their eggs singly or just 2 or 3 together. Eggs are very small (1mm in diameter).
Clutch Size: Females can lay 400-1,500 eggs per year.
Egg Habitat: Females deposit their eggs in shallow still water, attached to the bottom or to submerged vegetation, rocks or sticks.
Time to hatch: 6-12 days.

Spring Peeper eggs (look closely for the small round eggs). Photo: Jim Wolford. Photo from Nova Scotia

Wood Frogs
Time: Early spring (late March to early April)
Description: Wood Frogs lay egg masses at communal sites. When first laid, egg masses are very compact, but after they absorb water, they swell to 6 - 10 cm. Communal spawning is thought to help keep the eggs from freezing because the small black embryos, which absorb heat, and the thick jelly mass, which acts as an insulator, can raise the temperature within a large cluster to 6C higher than the surrounding water. Wood Frog egg masses may also contain green algae. Individual eggs are 2mm in diameter.
Clutch Size: Each mass contains 500-1,200 eggs, a much greater number than Yellow-spotted Salamanders.
Egg Habitat: Egg masses are laid in any body of water near on in woods. These water bodies may be ephemeral. Females prefer small ponds that are well shaded by trees. Egg masses are attached to submerged sticks or vegetation with the top of the egg masses at the surface.
Time to hatch: 15-20 days, depending on the water temperature.

 
Photo: Jim Wolford. Photo from Nova Scotia.


Leopard Frogs
Time: Spring (mid-April to mid-May)
Description: Leopard frogs lay their eggs in loose, flattened, oval-shaped masses.  Egg masses are 8-13 cm in diameter. Individual eggs are 1-2mm.
Clutch size: Egg masses contain 2,000-6,000 eggs.
Egg Habitat: Females lay their eggs in the shallows of ponds, lakes, cattail marshes or drainage ditches. Eggs are attached to submerged sticks or vegetation. The egg masses are in shallow water such that the underside of the egg mass rests at the bottom and topside breaks the surface of the water.
Time to hatch: 13-20 days.

 
Photo: Nova Scotia Museum of Natural History. Photo from Nova Scotia.

Pickerel Frogs
Time: Late spring (May)
Description: Eggs are greenish or light brown at one end and yellowish or white at the other end. Eggs are laid in globular masses. Egg masses are 5-10 cm in diameter and individual eggs are 2 mm in diameter.
Clutch Size: Each egg mass contains 800-1,800 eggs.
Egg Habitat: Females attach the egg masses to submerged sticks or vegetation and tend to lay their eggs in gently flowing streams and cool shaded woodland ponds.
Time to hatch: 12-18 days.

 
Photo: Scott Egan. Photo from Rhode Island.

Mink Frogs
Time: Summer (July)
Description: Females lay globular egg masses that are 7.5 - 15 cm in diameter.
Clutch size: There are 2,000-4,000 brown-black eggs in each egg mass.
Egg Habitat: Females lay eggs in vegetated coves of lakes or slow-moving vegetated streams and attach their egg masses to submerged sticks or vegetation. Egg masses drop to the bottom after laying and can be quite deep (up to 2m below the surface), which means that they are seldom observed. Eggs are generally laid in permanent bodies of water because Mink Frog tadpoles require a year to develop.
Time to hatch:
No records available.


Photo: Jim Wolford. Photo from Newfoundland.

Green Frogs
Time: Summer (early June through July)
Description: Female Green frogs lay their eggs as floating pancake rafts that stick to vegetation. The rafts are only one or two eggs thick, an adaptation that exposes all the embryos to warm summer air temperatures and speeds-up development. Individual eggs are 1-1.5mm in diameter. Egg masses are usually less than 30 cm in diameter.
Clutch Size: Each egg mass contains 1,000-4,000 eggs.
Egg Habitat:
Green Frogs lay their eggs close to shore in vegetated areas. Eggs are generally laid in permanent water bodies because tadpoles take a couple of years to develop.
Time to hatch: Embryos develop so quickly that small tadpoles hatch within four days.

 
Photo: Jim Wolford. Photo from Nova Scotia.

Bullfrogs
Time: Summer (mid-June through July)
Description: Like Green frogs, Bullfrogs also lay their eggs as floating pancake rafts but the egg mass can be several layers thick. Egg masses are usually more than 30 cm in diameter.
Clutch Size: Egg masses contain 10,000-20,000 eggs, many more than a Green frog egg mass.
Egg Habitat: Eggs are laid on the water surface among aquatic vegetation. Eggs are black and white and measure 1.2-1.8mm in diameter. Capsules around eggs are not distinguishable. Bullfrog eggs are generally found in deeper water where lily pads grow. Green Frog eggs are closer to shore.
Eggs are generally laid in permanent water bodies because tadpoles take a couple of years to develop.
Time to hatch: 4-5 days.

We do not have any photos of Bullfrog eggs. If you have a good picture, we would love to use it!


The information on this web page was taken from:

A Virtual Exhibit on Canada's Biodiversity: Focus on Amphibians
The Canadian Amphibian and Reptile Conservation Network
A guide to frog egg identification and metamorphic timing
Gilhen, J. 1984. Amphibians and Reptiles of Nova Scotia. The Nova Scotia Museum. Halifax, NS.

Halliday, T. and K. Adler. 1991. The Encyclopedia of Reptiles and Amphibians. Facts on File Inc. New York.
Hunter, M.L. Jr., A.J.K. Calhoun, and M. McCollough. 1999. Maine Amphibians and Reptiles. The University of Maine Press. Maine.
Petranka, J.W. 1998. Salamanders of the United States and Canada. Smithsonian Institution. Washington.

Stebbins, R.C. and N.W. Cohen. 1995. A Natural History of Amphibians. Princeton University Press. New Jersey.

All photos used with permission.


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