The impossible predicament of the death newts

Evolutionary costs, selection pressure, and “luck”

• Long back-and-forth over the article’s claim that tetrodotoxin resistance must be costly.
• One side: many species never encounter TTX, so there’s simply no selection pressure; evolution has no “feature list.” Absence of a trait need not imply a cost.
• Other side: in evolutionary game-theory terms, any trait has a fitness “price”; if a powerful, clearly useful trait doesn’t spread widely, that suggests it’s not cheap. Cost can be metabolic, developmental, or in constrained future options.
• Debate over how much to label evolution “luck”: some say evolutionary innovation paths are fundamentally contingent and stochastic; others argue that once constraints and feedback loops are in place, outcomes become relatively predictable and calling it “luck” is misleadingly broad.

Examples: vitamin C, brains, and trait loss

• Vitamin C synthesis: some argue its loss in primates shows traits can disappear “for free” when diet makes them redundant. Others counter that multiple unrelated lineages losing the same gene hints at subtle selective pressures or drift, not pure neutrality.
• Human brain vs muscle trade-offs: disagreement over how strong the evidence is that weaker jaw or limb musculature directly “paid for” bigger brains; citations raised but critiqued as over-interpreted correlations.
• General point: trait gain/loss is almost always multi-causal, and simple “just-so” stories are suspect.

Tetrodotoxin resistance and trait persistence

• Some commenters stress that maintaining any trait requires ongoing selection against entropy; traits not under pressure drift or disappear faster if costly, slower if cheap.
• Discussion of how much mortality is needed for protective alleles to spread; one reply notes that what matters is relative reproductive output, not cause of death per se.

How dangerous are rough-skinned newts to humans?

• Multiple people report freely handling these newts as children or in fieldwork with no serious issues, suggesting the article dramatizes risk.
• One documented fatality from deliberately swallowing a whole newt is cited; commenters infer that casual skin contact is rarely lethal if you don’t ingest toxin.
• One mushroom-foraging anecdote: handling a newt, then mushrooms, likely caused short-lived illness—seen as a near miss for more serious poisoning.
• Several conclude that human poisoning is rare despite high theoretical toxicity.

Predator–prey dynamics, mimicry, and sequestered toxin

• Interest in the snakes’ “second-order” use of TTX: storing it in their livers to poison their own predators.
• Some question how strong a selective benefit this really is, since the snake usually dies when eaten; benefits might accrue via predators learning to avoid that prey type or via heritable prey preferences.
• Discussion of mimic species that copy warning coloration and free-ride on the signal, complicating simple “honest signal” stories.
• Clarification (via Wikipedia) that garter snakes “taste test” newts by partially swallowing them and either finishing or rejecting based on toxicity.

Foraging, mushrooms, and risk vs reward

• Mushroom-foraging tangent: one camp argues wild mushroom calories aren’t worth the risk and effort; others respond that calories are the wrong metric—people forage for flavor, variety, exercise, and satisfaction.
• Poisoning statistics and risk comparisons are debated, along with the idea that careful species selection can make foraging relatively safe.

Miscellaneous reactions

• Many praise the article’s writing and enjoy the “death newts” framing and related octopus piece.
• Side notes on aposematic coloration, how newts are perceived as cute and common in the PNW, and minor language/abbreviation jokes (“teal deer,” “newts” vs “news”).