Pennterra is a science fiction novel by American author Judith Moffett, first published in 1987. Isaac Asimov wrote an introduction for the book and published it under his "Isaac Asimov Presents" series. Pennterra was reprinted in 2009 by Fantastic Books, an imprint of Warren Lapine's Wilder Publications.
Plot
Quaker colonists founded a colony on a planet they dubbed Pennterra. They soon discovered the planet was already inhabited, by a species they dub the "hrossa". They put forward a number of conditions to the colonists, saying that they must not leave the valley they landed in, must not use machinery, and should keep their population about the same as the time they landed, approximately 600. The Quakers agree with these restrictions, and set up a camp called Swarthmore, in the valley they call the Delaware.
The hrossa, being capable of transferring their emotions onto others, often tapped into the Quakers as they held meeting for worship. This leaves a number of them much more tolerant of the hrossa conditions. Several, including George Quinlan and his son Danny, become more closely acquainted with the hrossa. At times they visit a nearby village called Lake-Between-Falls and develop a friendship with one of its elders, KliUrrh.
However, as the story begins a second colony ship arrives from Earth. These colonists, called the Sixers, are more skeptical of the hrossa request, and enter talks with the Quakers. For the most part, the Sixers are adamant about colonizing the planet with machinery, putting their own survival above the hrossa. However, two members of the crew, Maggie and Byron, along with Quakers Katy and George visit Lake-Between-Falls hoping for permission for a coastal town of their own. However, KliUrrh denies the request, saying that they must follow the same conditions given to the Quaker colonists. He explains that their god TuwukhKawan will never allow this, and they would be destroyed if they violate the request.
Many of the Quakers take this as representing a legitimate threat, but the Sixers do not see it as serious and believe the Quakers have simply been compromised by their contact with the hrossa. With permission from the hrossa, a team of Quakers come to Lake-Between-Falls to learn more about the hrossa and the planet in general, in order to get an idea of the threat to the Sixers.
The team consists of George, Swarthmore's de facto leader; his son, Danny, who is capable with the hross language; Katy, a psychologist; Alice, an exobiologist; and Bob, an amateur anthropologist. Initially, they make little progress, as the sexuality of the hross is transmitted to the team, making it difficult to do any work. This is especially problematic for Danny, who at age 12 has begun puberty. In separate encounters, Alice has sex with George, and Katy with Bob. It soon becomes apparent that free-for-all sex might be necessary to keep them at work, but George initially resists due to his son's presence. Another day, Katy allows Danny to dry hump her, to George's unease. However, he gives in and soon the five have regular intercourse with one another, including, after some time, Danny with his father.
This makes it easier for the team to work. Among their discoveries, they find out that the hermaphroditic hrossa typically give birth to only one child in a lifetime, and few die early. The occasional second birth makes up for those that do, and the population thus tends to remain stable. Going on a hunt with the hrossa, they learn that they hunt by transmitting a message of "hunger", which brings animals sacrificially to them. The hrossa have sexual intercourse with the animals, and then beat them with a club. The Quakers also tell many stories to the hrossa, hoping to trigger a response and learn more about the planet's natives. Finally, at Thanksgiving, the team leaves back to Swarthmore, and explain their findings to the town.
The team goes back for another month, but have little more success. Returning to camp, Danny has difficulty readjusting. Missing the hrossa form of sexuality, he finds himself having sex with sheep, and on a couple of occasions, the sympathetic Katy. Danny, being the only person his age in the town besides a kid named Jack, finds life back home insufferable. When Jack is offered to stay for some time in the new Sixer village, Danny is adamant about going there as well.