Andrews, K.S., Levin, P. S., Katz, S. L., & Farrer, D.. (2007). Acoustic monitoring of sixgill shark movements in Puget Sound: evidence for localized movement.  Canadian Journal of Zoology, November 2007 85-96.  https://doi.org/10.1139/Z07-088 

• In this paper, the authors suprisingly describe sixgill sharks in Puget Sound as homebodies, often sticking to the same small areas 76% of the time. Interestingly, larger sharks moved even less than smaller ones, suggesting these giant predators prefer staying in their favorite local neighborhoods rather than wandering far and wide.

Andrews, K.S., Williams, G. D., & Levin, P. S.. (2010).  Seasonal and Ontogenetic Changes in Movement Patterns of Sixgill Sharks. PLosOne, 2010 Sep 8 https://doi.org/10.1371/journal.pone.0012549 

• In a follow up paper, the authors find Sixgill sharks are surprisingly loyal residents, often staying in Puget Sound for years and returning to the exact same favorite spots each season. They follow a predictable routine of moving north in the spring and south in the fall, but they suddenly double their swimming speed just before they finally decide to leave for the open ocean. This "hurry-up" behavior is a fascinating signal that these long-term locals are transitioning into a new, adventurous phase of their lives.

Levin, P. S., Horne, P., Andrews, K. S., & Williams, G.. (2012). An empirical movement model for sixgill sharks in Puget Sound. Current Zoology, Volume 58, Issue 1, 103-115. https://doi.org/10.1093/czoolo/58.1.103 

• For this research, the authors looked at both the daily movements and the long term movements.  They discovered that sixgill sharks are disciplined "homebodies" who follow a predictable daily commute, often returning to the same starting spot every single night. However, they also lead a double life: to cover the massive distances seen over several months, they must perform sudden, high-speed sprints that are so rare they are almost never caught during normal daily tracking. This reveals a fascinating balance where these deep-sea giants maintain a quiet local routine while taking occasional, lightning-fast "cross-country" trips.

Griffing, D., Larson, S., Hollander, J., Carpenter, T., Christiansen, J., Doss, C.. (2014) Observations on Abundance of Bluntnose Sixgill Sharks, Hexanchus griseus, in an Urban Waterway in Puget Sound, 2003-2005.  PLos One, 2014 Jan 27, 9.  https://doi.org/10.1371/journal.pone.0087081 

• Researchers discovered that the waters right next to downtown Seattle are a popular seasonal "hangout" where sixgill sharks gather in much higher numbers during the summer. Fascinatingly, every single shark spotted was a "teenager" (subadult), suggesting these young giants specifically use urban bays as a safe nursery to grow up before heading to the deep ocean. Many of these sharks are remarkably loyal to their favorite spots, with some individuals returning to the exact same research station nearly a year later. 

Lowry, D., Larson, S., Griffing, D.. (2016) Feeding Behavior of Subadult Sixgill Sharks (Hexanchus griseus) at a Bait Station. PLos One, May 31 2016.  https://doi.org/10.1371/journal.pone.0156730 

• Using underwater cameras at the Seattle Aquarium, researchers discovered that sixgill sharks are surprisingly tactical eaters, using specialized "sawing" and "tearing" motions to break apart large meals. These ancient giants even perform cautious "preparatory bites" to test their food and can actually pop their upper jaws forward to get a better grip—a sophisticated trick that helps them thrive as versatile hunters in the deep. 

Santander-Neto, J., Rincon, G., Juca-Queiroz, B., Paes da Cruz, V., Lessa, R.. (2022) Distribution and New Records of the Bluntnose Sixgill Shark, Hexanchus griseus (Hexanchiformes: Hexanchidae), from the Tropical Southwestern Atlantic.  Animals (Basel).  2022 December 26, 13.  https://doi.org/10.3390/ani13010091 

• In the tropical waters off Brazil, scientists discovered that sixgill sharks likely form permanent "resident" communities around underwater mountains and islands, often appearing in much shallower water than expected. These mysterious giants also have a fascinating "strength in numbers" mating strategy; a single mother can have a massive litter of over 100 pups with up to nine different fathers, a clever trick that helps her offspring stay genetically diverse and resilient.

Gallagher, A. J., de Silva, C., Delaney, D., Harris, S. D., Phillips, B.T., Shipley, O. N., Sulikowski, J. A., Duarte, C. M., Giddens, J.. Novel behavioral observations and body scarring for the bluntnose sixgill shark (Hexanchus griseus) offer clues to reproductive patterns and potential mating events.  Frontiers in Marien Sciences. 14 April 2024. https://doi.org/10.3389/fmars.2024.1305487 

• Deep-sea cameras in the Bahamas captured rare evidence of sixgill shark "date nights," including a female covered in fresh bite marks that suggest intense and competitive mating encounters. Scientists also spotted a likely pregnant female and a bold individual who actually tried to wrestle with the heavy camera equipment, dragging it several meters across the ocean floor. These findings reveal that these mysterious giants may gather in specific deep-sea "neighborhoods" to breed and start their families.