9th Annual Call for Amorous Alligator Lizards

Starting in spring of 2015, we have made an annual call for photos of alligator lizard mating behavior. Now in the 9th year of this research project, we still need your help in crowdsourcing the study of mating activity. With the western US experiencing the highest rainfalls in several decades, this is an especially interesting year, so please help us spread the word that we want photos of mating alligator lizards (Southern Alligator Lizards, Northern Alligator Lizards—we want them all; and observations of Madrean [aka Arizona] Alligator Lizard mating behavior in the fall—yes, they are fall breeders whereas the other species in the genus are spring breeders).

What does mating behavior look like? Here are some observations of mating behavior submitted to the RASCals project by iNat users in the last few weeks:
-@thatship21 (aka Becca Woods) observed this pair likely mating in San Diego County on April 19.
-CSU San Bernardino professor Breanna Putman (@breeput) observed this pair in a bite hold, but not mating on the CSUSB campus. Students in Bree's CSUSB herpetology class also made several observations of mating behavior, including this pair in Rancho Cucamonga.
-Long-time iNat superuser @scubabruin had wanted to see mating alligator lizards for several years. This year, she repeatedly checked her yard, documenting multiple alligator lizards, including this pair that were in a bite hold for 22 hours and 27 minutes.

What can you do:

1. Keep an eye out for mating pairs. When in the bite hold, they can end up in surprisingly exposed areas like on a lawn, in a driveway, or in the middle of the sidewalk. Sometimes, they stay a bit more hidden, such as on the edge of a shrub, where they can get dappled sunlight throughout the day. In about 5% of observations, the pairs are above the ground in trees or atop walls or fences.
2. Spread the word. The chance of any one person seeing this is quite low, but if you mention this research on Twitter, Facebook, or Nextdoor you will almost certainly reach someone who will see mating behavior this year or has seen it in past years (and if people have photos from past years and know where they took the photo, then we want that observation too). For example, @cdegroof received this photo from a friend who knew he was interested in reptiles, and Chris posted it to iNaturalist to be included in this study. If you want to promote this project, you can send around our project webpage for more info:
Or this YouTube video:

What have we learned with all these observations? Here are three discoveries so far.

1. Crowdsourcing is an incredibly effective way to study events that are rarely observed by any one person. Before we started this project, there were only four dates reported in the scientific literature for when Southern Alligator Lizards had been observed breeding. We knew we could get more observations through community science, by crowdsourcing the study of this rarely documented behavior. We have now accumulated 798 observations of mating Southern Alligator Lizards, and 143 observations of mating Northern Alligator Lizards (as of May 15; these numbers will be out of date within 12 hours of publishing this). We are pretty sure that through community science, we have generated the largest dataset ever on lizard mating!

2. Weather has a huge impact on the timing of the breeding season. Cooler and wetter weather will delay the start of the mating season. The 2023 season is the best example of this. With record rainfall and cooler winter and spring temperatures, the 2023 mating season is roughly one month behind the 2022 season, which was a below-average rainfall year. Mating activity starts at the southern end of the range, and then sweeps northward and upward in elevation with increasing temperatures. In 2022, the final San Diego County mating observation was April 25, but in 2023, we are still getting San Diego County observations at low elevations in mid May and should see observations from higher elevations into June.

3. Lizards can stay paired up for over two days! In some pairings, the male maintains the bite hold for a long time. Over the course of this bite hold, the pair may mate multiple times. How do we know this? For some pairings, dedicated community scientists check back on lizards repeatedly, sending me photos each time they relocate the pair. We can then learn duration of the pairing. In a few cases, we can use the photos to determine whether they are in the bite hold and mating, or in the bite hold and not mating allowing us to determine if they mate multiple times.

What to look for? During mating season, males search out females. The male bites the female on her neck or head and may hold her this way for several days. Early in the encounter, the two may engage in a bit of a wrestling match (if you see this, please try to get videos). Sometimes, a second male shows up and we get even more interesting observations! About 9% of all observations involve these threesomes.

When to look? Now through June. For the Southern Alligator Lizard, mating activity is still happening at the southern end of the range and just getting started at more northern and higher elevation locations. For the Northern Alligator Lizard, breeding is also just getting started and should continue through June across much of their range, with lizards at higher elevation populations breeding later (possibly into July---but who knows given snow fall levels in some areas this year).

Where to look? Alligator lizards can be found from coastal sand dunes to high elevations in our mountains. And they do better than any other local lizard in urban areas. When in the bite hold, pairs are often found out in the open, on driveways, sidewalks, lawns, and in yards. It is also possible to find pairs several feet off the ground on fences and in shrubs.

How to document? Take photos! If the pair is actively wrestling, please take video as well. We are especially interested in how long pairs remain in the mating hold, so please check back every few hours and search for the pair in the general area. Please upload photos to iNaturalist. If you are in Southern California, please tag observations to the RASCals project. If you are encouraging others to submit observations, they can also email photos to nature@nhm.org.

Posted on May 16, 2023 02:33 AM by gregpauly gregpauly


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