While hand-watering my yard with a hose, noticed what appeared to be lizards wrestling in some shrubs. One had another locked on its head. 

BTW, I refrain from the use of insecticide on my property because it can cause problems for the naturally indigenous lizards. See, they eat verminous insects like spiders and other unpleasant, intrusive critters. I admire spiders as a species (along with ants et al) as engineering marvels, but they can be problematic for humans living in their domain.  Lizards are immune to spider venom and therefore prey on spiders at will – which lessens the population of spiders. 

Mind it's not rare to find a healthy Black Widow or Brown Violin hanging around but the lizards eat a lot of them along with crickets. In the past, I've applied USDA-approved (rolls eyes) insecticide to the property because ants/spiders/crickets were intruding into the house. The population of the lizards went down temporarily, but the bugs just moved indoors (garage, under the house, etc) and came back. 

I figured out that the lizards were far more-effective at reducing the insect population on my small property than poison. So the poison was discontinued. The lizards came back, I cleaned up debris/foliage around the base-boards, and all was well for many moons. No insecticide.

The larger lizard was what is known as an Alligator Lizard (grows up to 18”) with the smaller a Blue Belly (Western Fence Lizard) about 8 inches max, in it’s grip (jaws clamped hard over the head). I recognized that the Alligator Lizard was not a regular to the property, so I acted to protect the Blue, which was "one of mine". I turned the hose at high pressure on the Alligator Lizard briefly. He reacted to the force of the water, but did not release grip. I turned the high-pressure stream at him again, and kept it there for a few seconds (not wanting to harm either of them). The Alligator Lizard moved away trying to drag the other deeper into the undergrowth. I turned up the pressure and applied a sustained stream to the Alligator Lizard and kept it there.  After about twenty seconds (!), the vicious, relentless Alligator finally released the Blue, which hurried off (though it seemed a little dazed). 

The Alligator Lizard retreated into the loam/leaves. I have not seen it on the property since our...disagreement. I’m guessing it moved on. PLEASE don’t mess with my lizard friends. They do great work, cause no trouble and don’t ask for much payment.