Behavior contributes heavily to me calling a shark a bull. They tend to be among the most aggressive & thuggish. I read somewhere that they have one of the highest testosterone levels of any animal on the planet.I disagree. Even the guides that dive all the time agreed the shark in my video #2 was a bull. To me, it looks exactly like the photos you shared of bulls. It even acted completely differently than the other sharks.
Let's just say we agree on one thing. They are all sharks.
I have sometimes seen them shoot straight up, completely out of the water, with the front end of a large fish falling on one side of them & the tail section falling on the other side. After that happened twice inside of 15 minutes within about 50 feet of the 12 foot skiff I was fishing out of, I decided it was time to go in for the day. I think that was probably the only time in 50+ years that I have been spooked off of fishing by anything other than terrible weather.
I had another time that I was fishing out of a 17' center console & the other guy in the boat hooked up on a large fish in sharky waters. He loosened the drag & we chased the fish for about a mile, then he tightened up & brought the fish boat side. Just as the fish got close, 2 bulls, that had followed us, made a b-line for the boat from two different angles. They hit the side of the boat so hard that the 250ish pound guy in the front of the boat got knocked off his feet. We lost that fish to 2 determined sharks that I assume to be bulls.
Makos, great whites, tigers, hammers & threshers are also known to be aggressive. I have one reliable report of a large mako biting the propeller of a running outboard & stalling it. The guy had pictures on his phone. He was a well respected tournament fisherman.
When the water gets chummed up & bloody, the sharks wake up and get frisky. In other conditions, I have dove in their proximity countless times with no issues.
Just north of Lake Worth Inlet, is a well known breeding spot for spinners. That may be part of the reason why so many of that type tend to be in this area.