The Amazing Life Cycle of the Red-spotted Newt

The Amazing Life Cycle of the Red-spotted Newt

As the year comes to an end, staff from our Integrated Watershed Monitoring Program (IWMP) have wrapped up their field season. Similarly, many animals are also winding down to prepare for winter.

An adult red-spotted newt. Photograph provided by CVC’s Jessica Consiglio.

Red-spotted newts endure the winter months differently depending on which part of their life stage they are in. Similar to frogs, red-spotted newts (Notophthalmus viridescens viridescens) go through multiple transformations. Frogs go through four life stages. First they lay eggs, which eventually transform into tadpoles. The tadpoles then become froglets which then grow into adult frogs.

The newt’s life cycle begins when adult breed in the spring and lay their eggs in ponds. The olive-coloured larvae hatch and look like tadpoles. They have frilly gills and limbs. They stay in the water until the end of summer or the beginning of fall. Then the magic begins! The aquatic larvae change into land-dwelling juveniles called red efts. The newt’s gills are absorbed into their skin, the tail loses its fin and the skin toughens to withstand drier conditions on land.

As the newt’s name implies, the most iconic change is the bright orange-red colour of their skin dotted with spots running down the backside. While they look so cute at this stage, the colour serves as a warning to predators that they are toxic to eat. Red efts live strictly on land for two to three years before they transform once more into their aquatic adult form. They become greenish-brown with a yellow belly and develop blade-like tails that help them swim.

The life cycle of Eastern newts. Diagram by Joven et al., 2019.

In winter, juvenile red efts hibernate beneath decaying logs and leaf litter on the forest floor, while adults usually remain active underwater in deep ponds.

We monitor how much downed wood is on the  forests to floor see if there is enough habitat for red-spotted newts and other wildlife.

A juvenile red eft walking on a bed of moss (left). A red eft crossing a decayed log (right). Photographs by CVC’s Jose Maloles.

Our field staff usually encounter one or two red efts during the field season. However, while conducting forest monitoring in Caledon this past fall, our staff were lucky enough to count 57 red efts crawling on the forest floor!

It rained the night before, making ideal conditions to see so many red efts during their fall migration. These little critters are more active after rain as they need the moisture to keep hydrated while travelling on the ground. They search for logs and other debris for shelter during the upcoming cold months. Similarly, CVC’s IWMP staff have returned indoors to summarize and analyze the data they collected, and plan for the new year.

Learn more about IWMP.

By CVC’s Jose Maloles, Technician, Watershed Monitoring

3 Comment
  • Neil M. - Inglewood says:

    Thanks Jose for the interesting narrative and great photos. I have been lucky enough to spot the terrestrial Red Eft a number of times over the years, including relatively large numbers (several dozen) in appropriate woodlands during the fall migratory period. I have also observed a few in the process of road crossing. They don’t move with any speed and would be at risk of being run over, so helping them finish the crossing seems advisable, just as you might do for a turtle. I did read once that the toxin they secrete is the same potent neurotoxin produced by the infamous puffer fish. They are cute, but best to resist the urge to pick them up, for numerous reasons.

    Thanks again!

  • Dara Murray says:

    great read thanks
    so important to leave the leaves

  • Bryan Frances Smith says:

    Thank you for this very interesting article.

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