FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

ROSS ATWOOD,                              
                Plaintiff-Appellant,
                                                 No. 06-35299
                v.
FORT PECK TRIBAL COURT                            D.C. No.
                                               CV-05-00165-RFC
ASSINIBOINE AND SIOUX TRIBES; and
                                                    OPINION
LINDA L. FLYNN HANSON,
             Defendants-Appellees.
                                          
         Appeal from the United States District Court
                 for the District of Montana
         Richard F. Cebull, District Judge, Presiding

                 Submitted November 6, 2007*
                     Seattle, Washington

                     Filed January 18, 2008

     Before: William C. Canby, Jr., Susan P. Graber, and
             Ronald M. Gould, Circuit Judges.

                    Opinion by Judge Graber




  *The panel unanimously finds this case suitable for decision without
oral argument. Fed. R. App. P. 34(a)(2).

                                 691
             ATWOOD v. FORT PECK TRIBAL COURT            693


                        COUNSEL

J. Gregory Tomicich, Billings, Montana, for the plaintiff-
appellant.

Ryan C. Rusche, Poplar, Montana, and Carol C. Johns, Wolf
Point, Montana, for the defendants-appellees.


                         OPINION

GRABER, Circuit Judge:

   This case involves a custody dispute concerning an Indian
child, Lexie. After the untimely death of Lexie’s mother,
Lexie’s maternal aunt, Defendant Linda L. Flynn Hanson,
sought custody through Defendant Fort Peck Tribal Court
(“Tribal Court”). The Tribal Court granted temporary custody
to Lexie’s maternal grandmother pending the outcome of the
custody dispute. Lexie’s non-Indian father, Plaintiff Ross
Atwood, then brought this action in federal district court,
challenging the jurisdiction of the Tribal Court and alleging
a substantive due process violation. The district court dis-
missed the case, relying on the domestic relations exception
to subject matter jurisdiction and on Plaintiff’s failure to
exhaust tribal court remedies.
694             ATWOOD v. FORT PECK TRIBAL COURT
   We hold that the “domestic relations exception,” a doctrine
divesting the federal courts of jurisdiction, applies only to the
diversity jurisdiction statute, 28 U.S.C. § 1332, and that the
district court erred by applying the domestic relations excep-
tion because federal question jurisdiction exists in this case
under 28 U.S.C. § 1331. We affirm the district court’s dis-
missal nonetheless, because Plaintiff failed to exhaust tribal
court remedies.

         FACTUAL AND PROCEDURAL HISTORY

   Plaintiff and Lexie’s mother never married. In late 1997,
when Lexie was two years old, Plaintiff filed a petition for
custody in the Tribal Court. After a hearing, the Tribal Court
entered a custody agreement for Lexie on February 20, 1998.
That agreement granted the parents “joint legal custody of the
child, with the Mother to have physical custody, and the
Father having [specified visitation rights].” The agreement
also stated that “the Fort Peck Tribal Court, Fort Peck Indian
Reservation shall continue to have jurisdiction over this mat-
ter.”

   On July 16, 2005, Lexie’s mother died, and Lexie was
taken to stay with her maternal grandmother. Lexie’s maternal
aunt, Defendant Hanson, thereafter petitioned the Tribal Court
for custody of Lexie.1 On September 23, 2005, that court
ordered that Lexie remain in the custody of her maternal
grandmother pending the outcome of the petition. Lexie
remains in the physical custody of her maternal grandmother,
and the custody case remains pending before the Tribal Court.

   On October 7, 2005, two weeks after the Tribal Court
issued its order, the Thirteenth Judicial District Court of Mon-
  1
    The record is not entirely clear on the status (Indian or non-Indian) of
Defendant Hanson and of Lexie’s maternal grandmother. Determination of
those factual questions is unnecessary to the resolution of the issue before
us.
              ATWOOD v. FORT PECK TRIBAL COURT                695
tana granted immediate custody of Lexie to Plaintiff. The
state court’s order shows that the state court was aware of the
1998 custody agreement, but gives no indication that it was
aware of the Tribal Court’s recent order. According to the
federal district court in this case, “[a]pparently, the Thirteenth
Judicial District Court terminated enforcement upon learning
of the pending tribal court matter.” The parties do not dispute
that finding.

   On December 29, 2005, Plaintiff filed a complaint in fed-
eral district court. The complaint alleges that the Tribal
Court’s order violates his substantive due process right to par-
ent his child and that Defendant Hanson lacks standing in
Tribal Court. Plaintiff sought injunctive relief, specifically, an
order requiring that Lexie’s grandmother return Lexie to him,
an order divesting the Tribal Court of jurisdiction, and an
award of custody. The complaint alleges both federal question
jurisdiction and diversity jurisdiction.

   On March 8, 2006, the district court granted Defendants’
motion to dismiss the complaint. The district court held that
the domestic relations exception divested it of jurisdiction
and, in the alternative, that it would choose to abstain from
intervening in a domestic relations matter that was pending in
a tribal court. Plaintiff timely appealed.

                  STANDARD OF REVIEW

   We review de novo whether we have subject matter juris-
diction. Schnabel v. Lui, 

, 1029 (9th Cir. 2002).
We also review de novo “[w]hether exhaustion of tribal court
remedies is required.” Boozer v. Wilder, 

, 934
(9th Cir. 2004).
696             ATWOOD v. FORT PECK TRIBAL COURT
                            DISCUSSION

  A. Subject Matter Jurisdiction and the “Domestic
  Relations Exception”

   [1] Plaintiff’s complaint alleges that “[t]he maternal aunt
has no standing [in Tribal Court] to petition for custody of the
child” and that the Tribal Court’s order is “a substantive vio-
lation of Plaintiff’s constitutional right to parent his child.” In
other words, Plaintiff alleges that “a tribal court has exceeded
the lawful limits of its jurisdiction.” Nat’l Farmers Union Ins.
Cos. v. Crow Tribe of Indians, 

, 853 (1985).
“Non-Indians may bring a federal common law cause of
action under 28 U.S.C. § 1331 to challenge tribal court juris-
diction.” 

(citing Nat’l 

). Federal courts therefore have subject matter
jurisdiction under the federal question jurisdiction statute, 28
U.S.C. § 1331, because the case arises under federal common
law.2 Nat’l 

.

   [2] Both in his complaint and before the district court,
Plaintiff asserted subject matter jurisdiction on two grounds:
federal question jurisdiction, 28 U.S.C. § 1331, and diversity
jurisdiction, 28 U.S.C. § 1332. The district court expressly
declined to decide “whether this Court has federal question or
diversity jurisdiction” and held that, regardless, the “domestic
relations exception to federal jurisdiction” applied. The
Supreme Court has long recognized that, when the relief
sought relates primarily to domestic relations, a doctrine
referred to as the domestic relations exception divests federal
courts of jurisdiction. See, e.g., In re Burrus, 

(1890); Barber v. Barber, 62 U.S. (21 How.) 582 (1858).
  2
    Because we have subject matter jurisdiction under § 1331, we need not
determine whether an alternative basis for jurisdiction also exists. See

n.2 (holding that jurisdiction exists under federal
common law and declining to address the plaintiff’s alternative jurisdic-
tional theory).
              ATWOOD v. FORT PECK TRIBAL COURT               697
Plaintiff argues that the domestic relations exception does not
apply in this case, because subject matter jurisdiction exists
under the federal question jurisdiction statute, § 1331, and the
domestic relations exception applies only to the diversity
jurisdiction statute, § 1332. We agree.

   The Supreme Court discussed the nature of the domestic
relations exception at length in Ankenbrandt v. Richards, 

(1992). The Court traced the history of the exception
and concluded, first, that the exception is not of constitutional
dimension. 

That is, “the Constitution does not
exclude domestic relations cases from the jurisdiction other-
wise granted by statute to the federal courts.” 

Court held, the diversity jurisdiction statute does
exclude such cases. In reasoning to that conclusion, the Court
examined the text and history of the diversity jurisdiction stat-
ute. 

The Court held that the exception derived from
Congress’ intent to exclude domestic relations cases from the
predecessor to 28 U.S.C. § 1332. 

When Congress
later amended the diversity statute, it meant to leave in place
the domestic relations exception. 

The Court
concluded that, in cases falling within the scope of the excep-
tion to § 1332, federal courts lack jurisdiction. 

   [3] In sum, Ankenbrandt held that the domestic relations
exception was not of constitutional dimension, but rested on
Congress’ intent in enacting the diversity jurisdiction statute,
28 U.S.C. § 1332. Although Ankenbrandt did not address
whether the exception applies to the federal question jurisdic-
tion statute, 28 U.S.C. § 1331, the Court’s reasoning plainly
does not apply to that statute. We therefore join the Fourth
and Fifth Circuits in holding that the domestic relations
exception applies only to the diversity jurisdiction statute. See
United States v. Bailey, 

, 1231 (5th Cir. 1997);
United States v. Johnson, 

, 481 (4th Cir. 1997);
see also Flood v. Braaten, 

, 307 (3d Cir. 1984)
698           ATWOOD v. FORT PECK TRIBAL COURT
(reaching the same conclusion in a case pre-dating Anken-
brandt).

   Our holding today is driven by the Supreme Court’s rea-
soning in Ankenbrandt, but it also is consistent with our cases
pre-dating Ankenbrandt. See Csibi v. Fustos, 

,
136 n.4 (9th Cir. 1982) (“Thus, domestic relations cases are
within the Article III judicial power of the federal courts, but
outside the power bestowed by Congress in the diversity stat-
ute.”). Of note, the First Circuit mistakenly identified the
Ninth Circuit as the only circuit to hold the opposite: that the
domestic relations exception applies to more than diversity
actions. See Mandel v. Town of Orleans, 

, 271
& n.3 (1st Cir. 2003) (citing Thompson v. Thompson, 

, 1558 (9th Cir. 1986) (per curiam)). We disagree
with the First Circuit’s characterization of Thompson. In that
case, we looked to the policies underlying the domestic rela-
tions exception for guidance in answering a statutory interpre-
tation question; we did not apply the exception at 

. In any event, we clarify today that the domestic
relations exception applies only to the diversity jurisdiction
statute.

   [4] In conclusion, subject matter jurisdiction exists in this
case under § 1331 and federal common law. The domestic
relations exception does not apply.

  B.   Exhaustion of Tribal Court Remedies

   [5] In dismissing the case, the district court also relied on
the fact that Plaintiff had not exhausted tribal court remedies.
Under the doctrine of exhaustion of tribal court remedies,
relief may not be sought in federal court until appellate review
of a pending matter in a tribal court is complete. Iowa Mut.
Ins. Co. v. LaPlante, 

, 17 (1987); see also Nat’l

(applying the doctrine); 

(same). “[T]he exhaustion rule . . . [i]s
‘prudential,’ not jurisdictional.” Strate v. A-1 Contractors,
               ATWOOD v. FORT PECK TRIBAL COURT                  699

, 451 (1997). As a matter of discretion, a district
court may either dismiss a case or stay the action while a
tribal court handles the matter. Nat’l 

. Because the parties do not dispute that the custody issue
is still pending before the Tribal Court, the district court prop-
erly exercised its discretion and dismissed this case due to
Plaintiff’s failure to exhaust tribal court remedies.

   Although the Supreme Court has crafted narrow exceptions
to the exhaustion rule, none applies here. There has been no
showing that Defendant Hanson asserted tribal jurisdiction in
bad faith or that she acted to harass Plaintiff. Nevada v. Hicks,

, 369 (2001). Nor can it be said that requiring
exhaustion in this case “would serve no purpose other than
delay.” 

marks omitted).

   Finally, it is not “plain” that tribal court jurisdiction is lack-
ing. 

471 U.S. at 459-60 & n.14). We have
equated that inquiry with whether jurisdiction is “colorable”
or “plausible.” Allstate Indem. Co. v. Stump, 

,
1075-76 (9th Cir. 1999). Here, tribal court jurisdiction almost
certainly is proper and therefore unquestionably is “plausi-
ble.” First, the 1998 custody agreement (the validity of which
Plaintiff does not challenge) states that the Tribal Court “shall
continue to have jurisdiction over this matter.” Second, Plain-
tiff availed himself of that forum voluntarily when the origi-
nal custody dispute arose in 1997, which is at least a
“colorable” basis for jurisdiction, even though the current
tribal court case was not initiated by Plaintiff. See Smith v.
Salish Kootenai Coll., 

, 1140 (9th Cir.) (en
banc) (“We hold that a nonmember who knowingly enters
tribal courts for the purpose of filing suit against a tribal
member has, by the act of filing his claims, entered into a
‘consensual relationship’ with the tribe . . . .”), cert. denied,

(2006). Third, the suit primarily concerns
Lexie, who is a member of the tribe. Although the rights of
non-member Plaintiff are affected, it is not clear that that fact
alone would strip the Tribal Court of jurisdiction.
700           ATWOOD v. FORT PECK TRIBAL COURT
                       CONCLUSION

   We hold that the domestic relations exception applies only
to the diversity jurisdiction statute, 28 U.S.C. § 1332. Because
federal courts have jurisdiction in this case under the federal
question jurisdiction statute, 28 U.S.C. § 1331, the district
court erred by applying the domestic relations exception.
Nonetheless, we affirm the district court’s dismissal of this
case because Plaintiff has not exhausted his tribal court reme-
dies.

  AFFIRMED.