“Because the male is concerned only with mating,” Ev said. “The female is concerned with ensuring the optimum survival of her offspring, which means she needs a strong mate or a smart one. The male doesn’t do all the courting, though. The females send out response signals to encourage and attract the males.”

“Like landing lights?” I said.

C.J. glared at me.

“Without those signals, the courtship ritual breaks down and can’t be completed,” Ev said.

“I’ll keep that in mind,” Carson said. He pushed back from the table. “Fin, if we’re gonna start in two days, we’d better take a look at the map. I’ll go get the new topographicals.” He went out.

C.J. cleared off the table, and I threw Bult off the computer and set up the map, filling in the two holes with extrapolated topographies before I went back over to the table.

Ev was bending over the map. “Is that the Wall?” he said, pointing at the Tongue.

“Nope. That’s the Tongue. That’s the Wall,” I said, sticking my hand in the middle of the holo to show him its course.

“I hadn’t realized it was so long,” he said wonderingly, tracing its meandering course along the Tongue and into the Ponypiles. “Which part is uncharted territory?”

“The blank part,” I said, looking at the huge western expanse of the map. The charted area looked like a drop in the bucket.

Carson came back in and called Bult and his umbrella over, and we discussed routes.

“We haven’t mapped any of the northern tributaries of the Tongue,” Carson said, circling an area in light marker. “Where can we cross the Wall, Bult?”

Bult leaned over the table and pointed stiffly at two different places, making sure his finger didn’t go into the holo.