Hey Southern Californians: We Want Your Photos of Alligator Lizard Sex

Yes, you read that right. We need your help to study Southern Alligator Lizard breeding biology. Starting as early as February 9, alligator lizards in Southern California start mating. So far in 2017, we have received no reports of amorous alligator lizards, but that is likely to change in the next few days. Weather forecasts predict rising temperatures and increased sunshine (woohoo!!!); in other words, the weather is looking good for the start of the 2017 alligator lizard breeding season.

What does alligator lizard courtship look like? Check out these photos submitted to the RASCals project during the 2016 breeding season: 

Three Southern Alligator Lizards observed by Xan Sonn March 21, 2016 engaged in courtship behavior in the courtyard of a Pasadena apartment complex.
https://www.inaturalist.org/observations/2821128

A pair observed in Coastal San Pedro by regular RASCals contributor CSPNL; Cheryl is especially observant and found paired up alligator lizards in her San Pedro backyard five times in 2015 and three times in 2016.
https://www.inaturalist.org/observations/2929389

Southern Alligator Lizards observed by Kat Halsey April 17, 2016 mating in a barn at the Los Angeles Zoo.
https://www.inaturalist.org/observations/2997229

Southern Alligator Lizards in a mating hold and very likely mating. Observed and photographed by Felix Langer and Teo Langer (aged 5 and 8, respectively when these lizards were observed April 10, 2016) with help from mom Ariel.
https://www.inaturalist.org/observations/2925244

Many people who see alligator lizard courtship might think the lizards are fighting or that one is even cannibalizing the other, but in fact, this is alligator lizard love. The male bites the female on her neck or head and then uses his tail to attempt to lift the female’s tail. The female may refuse these advances hoping instead a male more to her liking comes along and displaces the first male. As a result, the pair may stay in this position for more than a day. If the female does decide to mate, she lifts her tail allowing the male to insert his hemipenis into the female’s cloaca.

What’s a hemipenis? It’s the intromittent organ (an external organ specialized to deliver sperm while mating) of male lizards and snakes. In other words, it’s the lizard equivalent of the mammalian penis, except that lizards and snakes have two and can use the left or right hemipenis depending on which side is closest to the female. In some species, the hemipenes (this is the plural of hemipenis) are covered in barbs and spines, but in alligator lizards, the hemipenes are relatively smooth and lack these structures.

In 2015, we started using the RASCals project to study the breeding behavior of these lizards. One of the main questions is to understand whether urban and rural lizards breed at the same time. Urban areas tend to heat up more than surrounding rural areas; this is termed the urban heat island effect. If the lizards are using temperature as a cue for when to mate, we might then expect that urban lizards breed earlier.

The challenge with studying the breeding biology of these lizards is that it would be very difficult to get a large number of observations across different habitat types. However, we can solve this problem by crowdsourcing; we can ask thousands of people to keep an eye out and document any breeding observations by sending us photos.

This approach has worked well. Citizen scientists documented 19 cases of breeding behavior in 2015, and 20 in 2016. We have also received a number of photos from earlier years, all the way back to 2008. Based on these observations, breeding in coastal areas of Southern California can be as early as February 9th, or as late as May 3rd, but the peak of breeding tends to be mid-March through mid-April. We are already seeing interesting variation from year to year. In 2015, 13 of the 19 observations occurred in a single peak of activity between March 17 and April 1. In 2016, we saw two peaks of activity—breeding activity increased in mid-March, but then ceased as a series of cold fronts in late March and early April passed through Southern California. We then had a second peak of activity in mid-April with the return of warmer temperatures and sunny skies.

What will the breeding season be like in 2017? We should know the answer soon, but only with YOUR HELP? If you see courting or mating alligator lizards, please take a photo and submit it to the RASCals project. If you have photos from previous years, please submit those as well. As the breeding season progresses, I’ll update this journal entry with some of the discoveries.

ALLIGATOR LIZARD UPDATES
March 11. The 2017 breeding season is now officially under way. Jim Julian documented the first breeding pair, which he found in Anaheim. Check out the first 2017 observation here: http://www.inaturalist.org/observations/5285174

March 16. The 2017 breeding season is finally getting going. We received two reports of breeding alligator lizards today. I expect the peak of the breeding season will be now through early April, likely with a decrease in activity March 21-23, with the arrival of a cold front. Of the observations today, one was in southern San Diego County, and the other was on the Occidental College campus in Los Angeles. You can see the second observation here: http://www.inaturalist.org/observations/5378139

March 23. We are now up to 9 observations of breeding for the 2017 season, with observations from San Diego (4), Los Angeles (3), Orange (1) and Ventura (1) Counties. The anticipated cold front was relatively weak, and breeding was observed March 21 and 23 but only in San Diego Counties. Keep an eye out as we should be averaging about one new observation per day into early April. If you do see a pair, try to check back on them every few hours. CSPNL did this and found the pair together over a 31-hour period!!! You can see that observation here: http://www.inaturalist.org/observations/5397189

April 3. We are now up to 30 observations for the 2017 breeding season. This is the largest number of observations we have received during a single mating season since starting this study in 2015.

This journal entry was modified from an article I wrote for the Natural History Museum's "Nature in L.A." blog. You can read the original here: https://www.nhm.org/nature/blog/dear-los-angeles-we-need-your-photos-alligator-lizard-sex

Posted on February 28, 2017 04:40 PM by gregpauly