What follows is a collection of sources that in some way describe the Karankawa Indians’ customs:
 Diary of the Alarcón Expedition Into Texas
Author: Fray Francisco Céliz (I will write a Handbook of Texas entry)
Written in: 1718-1719
Description: In 1718, Governor of Texas Martin de Alarcón was tasked with establishing a mission and presidio on the San Antonio River, with resupplying the missions among the Caddos in East Texas, and with selecting potential settlement sites “for the purpose of repelling all foreign invasion or commerce.” During his expedition, Alarcón took twenty-nine troops, nineteen religious, and three Hasinai Indians to explore the Karankawas’ territory (pg 58). They brought trade goods in hopes of winning the trust of these coastal Peoples. Alarcón made contact with a group of eighteen Karankawas. After both parties exchanged goods, the Karankawas told Alarcón the location of the razed Fort Saint-Louis where he took official possession of the bay in the name of the Crown. Alarcón made no further contact with the Karankawas.
There are two known written accounts of Alarcón’s expedition into Texas. Fray Pedro Perez de Mezquía wrote a diary that covers a small portion of the expedition without any mention of Karankawas. Fray Francisco Céliz wrote an exhaustive journal of the expedition, which is attached to this entry. There is no extant record kept by Martín de Alarcón, the expedition leader.
(1) Two local Indians guiding the expedition (perhaps the Pacuache Indians) fled because of their fear of coastal Indians (pg 50).
(2) Two more Indian guides, a Moruame Indian and a Payaya Indian, fled the expedition. Again, likely a fear of conflict with the coastal Indians which demonstrates that these Coahuiltecan-speakers and the Karankawas must have been in a larger conflict (pg 59). The three Hasinai Indians who Talon labeled as being the “ancient enemies” of the Karankawas sometime in the late 1680s, did not abandon the expedition. This is likely because they had closer ties with the Spaniards and Alarcón’s expedition planned to head to Caddo lands after exploring the coast. A similar instance of Hasinai’s occurred in 1690 during Alonso de León’s second expedition into Texas, see Bolton, Spanish Exploration in the Southwest, 384.
(3) Alarcón’s party encounters two Karankawas, who upon seeing the expedition, “threw themselves into the water and crossed the cove by swimming” (pgs 64-65).
(4) Alarcón once again makes contact with Karankawas, this time a group of eighteen: two on the beach and four men, four women, and eight children in a single canoe (pgs 65-66). This impressively sized canoe is significant because past historians have incorrectly labeled Karankawas’ sea-faring vessels as simply being “logs upon which they sprawled on their stomachs and paddled with their hands.” Kathryn Stoner O’Connor, Presidio La Bahía (Austin: Von Boeckmann-Jones Co, 1966), 246.
(5) This group of eighteen Karankawas treats with the Alarcón party (pgs 65-67). Both groups talk peace through sign-language and gifts.
(6) A short distance out of the Karankawas’ land, an uncountable number of Aranama Indians sought to ally with the Spaniards. They asked for a mission to be placed near the razed location of Fort Saint Louis. This tells us that the Aranamas and Karankawas were on good terms as the proposed mission would be on both their lands. Moreover, Aranamas believed by acquiring a mission, they could acquire a somewhat regular stream of trade goods as the Hasinais enjoyed.
Further Reading: William C. Foster, Spanish Expeditions Into Texas (Austin: University of Texas Press, 2000), 127-143. Fritz L. Hoffmann, “The Mezquía Diary of the Alarcon Expedition into Texas, 1718,” The Southwestern Historical Quarterly 41, No. 4 (Apr, 1938): 312-323.
[1829-~1850] Reminiscences of Mrs. Annie Fagan Teal
Author: Annie Fagan Teal (need to write one)
Written in: 1897
Description: At the age of 83, Mrs. T.C. Allan interviewed Annie Fagan Teal, an early settler of Texas. A transcript of this interview has yet to be uncovered (it’s unlikely one exists). Allan edited her conversation with Teal into this piece originally published in a local Victoria magazine called By The Way. This source, then, is far removed from the time in which the events described occurred. And moreover, we are receiving information second-hand. Nevertheless, Teal accurately describes that the first settlers of Texas had multiple positive interactions with Karankawas. This is important because later historians and colonists depicted Karankawas as inherently hostile at the first sign of Whites.
(1) Annie Teal enters Texas in 1829 at the age of 15. Around this time she is welcomed in a near-by Karankawa camp and drank “beer” with these Peoples. By beer, she could plainly mean any sort of alcoholic beverage or perhaps a caffeinated drink that the Karankawas made out of the yaupon leaves. [317, 320]
(2) Cholera broke out among those living in Texas. Without a doubt, it affected Native Peoples. 
(3) Teal is married in 1833 at the age of 19. Invited to her wedding is the Karankawa chief Prudencia. 
(4) Teal describes Karankawas finding work among the early settlers. It also discusses Karankawas drinking whiskey. 
(5) Discusses a custom of Indians of the area sending a young child to the houses of colonists asking for lodging to test the true “friendship” of the colonizers. I have not found any corroboration of this elsewhere. 
(6) Teal says that “Mexican hirelings” killed a Karankawa child and that the Karankawas took revenge by killing six. When militia followed the Karankawas, they turned back when the Karankawa chief Antonique (Antonio) readied to fight them. 
(7) Teal tells that Tonkawas killed eleven Karankawas when the Karankawas planned to attack the De León colony. I have also not found any validation for this story, but that the Karankawas had a conflict with De León is well-known. So too that De León had crafted a strong relationship with the Tonkawa Peoples. [322-323]
Further Reading: Ana Carolina Castillo Crimm, De León: A Tejano Family History (Austin: University of Texas Press, 2003).